Opinion
WERDEGAR, J.Intel Corporation (Intel) maintains an electronic mail system, connected to the Internet, through which messages between employees and those outside the company can be sent and received, and permits its employees to make reasonable nonbusiness use of this system. On six occasions over almost two years, Kourosh Kenneth Hamidi, a former Intel employee, sent e-mails criticizing Intel’s employment practices to numerous current employees on Intel’s electronic mail system. Hamidi breached no computer security barriers in order to communicate with Intel employees. He offered to, and did, remove from his mailing list any recipient who so wished. Hamidi’s communications to individual Intel employees caused neither physical damage nor functional disruption to the company’s computers, nor did they at any time deprive Intel of the use of its computers. The contents of the messages, however, caused discussion among employees and managers.
On these facts, Intel brought suit, claiming that by communicating with its employees over the company’s e-mail system Hamidi committed the tort of *1347trespass to chattels. The trial court granted Intel’s motion for summary judgment and enjoined Hamidi from any further mailings. A divided Court of Appeal affirmed.
After reviewing the decisions analyzing unauthorized electronic contact with computer systems as potential trespasses to chattels, we conclude that under California law the tort does not encompass, and should not be extended to encompass, an electronic communication that neither damages the recipient computer system nor impairs its functioning. Such an electronic communication does not constitute an actionable trespass to personal property, i.e., the computer system, because it does not interfere with the possessor’s use or possession of, or any other legally protected interest in, the personal property itself. (See Zaslow v. Kroenert (1946) 29 Cal.2d 541, 551 [176 P.2d 1]; Ticketmaster Corp. v. Tickets.com, Inc. (C.D.Cal., Aug. 10, 2000, No. 99CV7654) 2000 WL 1887522, p. *4; Rest.2d Torts, § 218.) The consequential economic damage Intel claims to have suffered, i.e., loss of productivity caused by employees reading and reacting to Hamidi’s messages and company efforts to block the messages, is not an injury to the company’s interest in its computers—which worked as intended and were unharmed by the communications—any more than the personal distress caused by reading an unpleasant letter would be an injury to the recipient’s mailbox, or the loss of privacy caused by an intrusive telephone call would be an injury to the recipient’s telephone equipment.
Our conclusion does not rest on any special immunity for communications by electronic mail; we do not hold that messages transmitted through the Internet are exempt from the ordinary rules of tort liability. To the contrary, e-mail, like other forms of communication, may in some circumstances cause legally cognizable injury to the recipient or to third parties and may be actionable under various common law or statutory theories. Indeed, on facts somewhat similar to those here, a company or its employees might be able to plead causes of action for interference with prospective economic relations (see Guillory v. Godfrey (1955) 134 Cal.App.2d 628, 630-632 [286 P.2d 474] [defendant berated customers and prospective customers of plaintiffs’ cafe with disparaging and racist comments]), interference with contract (see Blender v. Superior Court (1942) 55 Cal.App.2d 24, 25-27 [130 P.2d 179] [defendant made false statements about plaintiff to his employer, resulting in plaintiffs discharge]) or intentional infliction of emotional distress (see Kisesky v. Carpenters’ Trust for So. California (1983) 144 Cal.App.3d 222, 229-230 [192 Cal.Rptr. 492] [agents of defendant union threatened life, health, and family of employer if he did not sign agreement with union].) And, of course, as with any other means of publication, third party subjects of e-mail communications may under appropriate facts make claims for *1348defamation, publication of private facts, or other speech-based torts. (See, e.g., Southridge Capital Management v. Lowry (S.D.N.Y. 2002) 188 F.Supp.2d 388, 394-396 [allegedly false statements in e-mail sent to several of plaintiff’s clients support actions for defamation and interference with contract].) Intel’s claim fails not because e-mail transmitted through the Internet enjoys unique immunity, but because the trespass to chattels tort— unlike the causes of action just mentioned—may not, in California, be proved without evidence of an injury to the plaintiffs personal property or legal interest therein.
Nor does our holding affect the legal remedies of Internet service providers (ISP’s) against senders of unsolicited commercial bulk e-mail (UCE), also known as “spam.” (See Ferguson v. Friendfinders, Inc. (2002) 94 Cal.App.4th 1255, 1267 [115 Cal.Rptr.2d 258].) A series of federal district court decisions, beginning with CompuServe Inc. v. Cyber Promotions, Inc. (S.D.Ohio 1997) 962 F.Supp. 1015, has approved the use of trespass to chattels as a theory of spammers’ liability to ISP’s, based upon evidence that the vast quantities of mail sent by spammers both overburdened the ISP’s own computers and made the entire computer system harder to use for recipients, the ISP’s customers. (See id. at pp. 1022-1023.) In those cases, discussed in greater detail below, the underlying complaint was that the extraordinary quantity of UCE impaired the computer system’s functioning. In the present case, the claimed injury is located in the disruption or distraction caused to recipients by the contents of the e-mail messages, an injury entirely separate from, and not directly affecting, the possession or value of personal property.
Factual and Procedural Background
We review a grant of summary judgment de novo; we must decide independently whether the facts not subject to triable dispute warrant judgment for the moving party as a matter of law. (Galanty v. Paul Revere Life Ins. Co. (2000) 23 Cal.4th 368, 374 [97 Cal.Rptr.2d 67,1 P.3d 658]; Norgart v. Upjohn Co. (1999) 21 Cal.4th 383, 404 [87 Cal.Rptr.2d 453, 981 P.2d 79]; Code Civ. Proc., § 437c, subd. (c).) The pertinent undisputed facts are as follows.
Hamidi, a former Intel engineer, together with others, formed an organization named Former and Current Employees of Intel (FACE-Intel) to disseminate information and views critical of Intel’s employment and personnel policies and practices. FACE-Intel maintained a Web site (which identified Hamidi as Webmaster and as the organization’s spokesperson) containing such material. In addition, over a 21-month period Hamidi, on *1349behalf of FACE-Intel, sent six mass e-mails to employee addresses on Intel’s electronic mail system. The messages criticized Intel’s employment practices, warned employees of the dangers those practices posed to their careers, suggested employees consider moving to other companies, solicited employees’ participation in FACE-Intel, and urged employees to inform themselves further by visiting FACE-Intel’s Web site. The messages stated that recipients could, by notifying the sender of their wishes, be removed from FACE-Intel’s mailing list; Hamidi did not subsequently send messages to anyone who requested removal.
Each message was sent to thousands of addresses (as many as 35,000 according to FACE-Intel’s Web site), though some messages were blocked by Intel before reaching employees. Intel’s attempt to block internal transmission of the messages succeeded only in part; Hamidi later admitted he evaded blocking efforts by using different sending computers. When Intel, in March 1998, demanded in writing that Hamidi and FACE-Intel stop sending e-mails to Intel’s computer system, Hamidi asserted the organization had a right to communicate with willing Intel employees; he sent a new mass mailing in September 1998.
The summary judgment record contains no evidence Hamidi breached Intel’s computer security in order to obtain the recipient addresses for his messages; indeed, internal Intel memoranda show the company’s management concluded no security breach had occurred.1 Hamidi stated he created the recipient address list using an Intel directory on a floppy disk anonymously sent to him. Nor is there any evidence that the receipt or internal distribution of Hamidi’s electronic messages damaged Intel’s computer system or slowed or impaired its functioning. Intel did present uncontradicted evidence, however, that many employee recipients asked a company official to stop the messages and that staff time was consumed in attempts to block further messages from FACE-Intel. According to the FACE-Intel Web site, moreover, the messages had prompted discussions between “[ejxcited and nervous managers” and the company’s human resources department.
Intel sued Hamidi and FACE-Intel, pleading causes of action for trespass to chattels and nuisance, and seeking both actual damages and an injunction *1350against further e-mail messages. Intel later voluntarily dismissed its nuisance claim and waived its demand for damages. The trial court entered default against FACE-Intel upon that organization’s failure to answer. The court then granted Intel’s motion for summary judgment, permanently enjoining Hamidi, FACE-Intel, and their agents “from sending unsolicited e-mail to addresses on Intel’s computer systems.” Hamidi appealed; FACE-Intel did not.2
The Court of Appeal, with one justice dissenting, affirmed the grant of injunctive relief. The majority took the view that the use of or intermeddling with another’s personal property is actionable as a trespass to chattels without proof of any actual injury to the personal property; even if Intel could not show any damages resulting from Hamidi’s sending of messages, “it showed he was disrupting its business by using its property and therefore is entitled to injunctive relief based on a theory of trespass to chattels.” The dissenting justice warned that the majority’s application of the trespass to chattels tort to “unsolicited electronic mail that causes no harm to the private computer system that receives it” would “expand the tort of trespass to chattel in untold ways and to unanticipated circumstances.”
We granted Hamidi’s petition for review.3
Discussion
I. Current California Tort Law
Dubbed by Prosser the “little brother of conversion,” the tort of trespass to chattels allows recovery for interferences with possession of personal property “not sufficiently important to be classed as conversion, and so to compel the defendant to pay the full value of the thing with which he has interfered.” (Prosser & Keeton, Torts (5th ed. 1984) § 14, pp. 85-86.)
Though not amounting to conversion, the defendant’s interference must, to be actionable, have caused some injury to the chattel or to the plaintiffs rights in it. Under California law, trespass to chattels “lies where an intentional interference with the possession of personal property has proximately *1351caused injury.” (Thrifty-Tel, Inc. v. Bezenek (1996) 46 Cal.App.4th 1559, 1566 [54 Cal.Rptr.2d 468], italics added.) In cases of interference with possession of personal property not amounting to conversion, “the owner has a cause of action for trespass or case, and may recover only the actual damages suffered by reason of the impairment of the property or the loss of its use.” (Zaslow v. Kroenert, supra, 29 Cal.2d at p. 551, italics added; accord, Jordan v. Talbot (1961) 55 Cal.2d 597, 610 [12 Cal.Rptr. 488, 361 P.2d 20, 6 A.L.R.3d 161].) In modem American law generally, “[trespass remains as an occasional remedy for minor interferences, resulting in some damage, but not sufficiently serious or sufficiently important to amount to the greater tort” of conversion. (Prosser & Keeton, Torts, supra, § 15, p. 90, italics added.)
The Restatement, too, makes clear that some actual injury must have occurred in order for a trespass to chattels to be actionable. Under section 218 of the Restatement Second of Torts, dispossession alone, without further damages, is actionable (see id., par. (a) & com. d, pp. 420-421), but other forms of interference require some additional harm to the personal property or the possessor’s interests in it. (Id., pars, (b)-(d).) “The interest of a possessor of a chattel in its inviolability, unlike the similar interest of a possessor of land, is not given legal protection by an action for nominal damages for harmless intermeddlings with the chattel. In order that an actor who interferes with another’s chattel may be liable, his conduct must affect some other and more important interest of the possessor. Therefore, one who intentionally intermeddles with another’s chattel is subject to liability only if his intermeddling is harmful to the possessor’s materially valuable interest in the physical condition, quality, or value of the chattel, or if the possessor is deprived of the use of the chattel for a substantial time, or some other legally protected interest of the possessor is affected as stated in Clause (c). Sufficient legal protection of the possessor’s interest in the mere inviolability of his chattel is afforded by his privilege to use reasonable force to protect his possession against even harmless interference.” (Id., com. e, pp. 421-422, italics added.)
The Court of Appeal (quoting 7 Speiser et al., American Law of Torts (1990) Trespass, § 23:23, p. 667) referred to “ ‘a number of very early cases [showing that] any unlawful interference, however slight, with the enjoyment by another of his personal property, is a trespass.’ ” But while a harmless use or touching of personal property may be a technical trespass (see Rest.2d Torts, § 217), an interference (not amounting to dispossession) is not actionable, under modem California and broader American law, without a showing of harm. As already discussed, this is the mle embodied in the Restatement (Rest.2d Torts, § 218) and adopted by California law *1352(Zaslow v. Kroenert, supra, 29 Cal.2d at p. 551; Thrifty-Tel, Inc. v. Bezenek, supra, 46 Cal.App.4th at p. 1566).
In this respect, as Prosser explains, modem day trespass to chattels differs both from the original English writ and from the action for trespass to land: “Another departure from the original mle of the old writ of trespass concerns the necessity of some actual damage to the chattel before the action can be maintained. Where the defendant merely interferes without doing any harm—as where, for example, he merely lays hands upon the plaintiffs horse, or sits in his car—there has been a division of opinion among the writers, and a surprising dearth of authority. By analogy to trespass to land there might be a technical tort in such a case .... Such scanty authority as there is, however, has considered that the dignitary interest in the inviolability of chattels, unlike that as to land, is not sufficiently important to require any greater defense than the privilege of using reasonable force when necessary to protect them. Accordingly it has been held that nominal damages will not be awarded, and that in the absence of any actual damage the action will not lie.” (Prosser & Keeton, Torts, supra, § 14, p. 87, italics added, fns. omitted.)
Intel suggests that the requirement of actual harm does not apply here because it sought only injunctive relief, as protection from future injuries. But as Justice Kolkey, dissenting below, observed, “[t]he fact the relief sought is injunctive does not excuse a showing of injury, whether actual or threatened.” Indeed, in order to obtain injunctive relief the plaintiff must ordinarily show that the defendant’s wrongful acts threaten to cause irreparable injuries, ones that cannot be adequately compensated in damages. (5 Witkin, Cal. Procedure (4th ed. 1997) Pleading, § 782, p. 239.) Even in an action for trespass to real property, in which damage to the property is not an element of the cause of action, “the extraordinary remedy of injunction” cannot be invoked without showing the likelihood of irreparable harm. (Mechanics’ Foundry v. Ryall (1888) 75 Cal. 601, 603 [17 P. 703]; see Mendelson v. McCabe (1904) 144 Cal. 230, 232-233 [77 P. 915] [injunction against trespass to land proper where continued trespasses threaten creation of prescriptive right and repetitive suits for damages would be inadequate remedy].) A fortiori, to issue an injunction without a showing of likely irreparable injury in an action for trespass to chattels, in which injury to the personal property or the possessor’s interest in it is an element of the action, would make little legal sense.
The dispositive issue in this case, therefore, is whether the undisputed facts demonstrate Hamidi’s actions caused or threatened to cause damage to Intel’s computer system, or injury to its rights in that personal property, such as to entitle Intel to judgment as a matter of law. To review, the undisputed *1353evidence revealed no actual or threatened damage to Intel’s computer hardware or software and no interference with its ordinary and intended operation. Intel was not dispossessed of its computers, nor did Hamidi’s messages prevent Intel from using its computers for any measurable length of time. Intel presented no evidence its system was slowed or otherwise impaired by the burden of delivering Hamidi’s electronic messages. Nor was there any evidence transmission of the messages imposed any marginal cost on the operation of Intel’s computers. In sum, no evidence suggested that in sending messages through Intel’s Internet connections and internal computer system Hamidi used the system in any manner in which it was not intended to function or impaired the system in any way. Nor does the evidence show the request of any employee to be removed from FACE-Intel’s mailing list was not honored. The evidence did show, however, that some employees who found the messages unwelcome asked management to stop them and that Intel technical staff spent time and effort attempting to block the messages. A statement on the FACE-Intel Web site, moreover, could be taken as an admission that the messages had caused “[e]xcited and nervous managers” to discuss the matter with Intel’s human resources department.
Relying on a line of decisions, most from federal district courts, applying the tort of trespass to chattels to various types of unwanted electronic contact between computers, Intel contends that, while its computers were not damaged by receiving Hamidi’s messages, its interest in the “physical condition, quality or value” (Rest.2d Torts, § 218, com. e, p. 422) of the computers was harmed. We disagree. The cited line of decisions does not persuade us that the mere sending of electronic communications that assertedly cause injury only because of their contents constitutes an actionable trespass to a computer system through which the messages are transmitted. Rather, the decisions finding electronic contact to be a trespass to computer systems have generally involved some actual or threatened interference with the computers’ functioning.
In Thrifty-Tel, Inc. v. Bezenek, supra, 46 Cal.App.4th at pages 1566-1567 (Thrifty-Tel), the California Court of Appeal held that evidence of automated searching of a telephone carrier’s system for authorization codes supported a cause of action for trespass to chattels. The defendant’s automated dialing program “overburdened the [plaintiffs] system, denying some subscribers access to phone lines” (id. at p. 1564), showing the requisite injury.
Following Thrifty-Tel, a series of federal district court decisions held that sending UCE through an ISP’s equipment may constitute trespass to the ISP’s computer system. The lead case, CompuServe Inc. v. Cyber Promotions, Inc., supra, 962 F.Supp. 1015, 1021-1023 (CompuServe), was followed *1354by Hotmail Corp. v. Van$ Money Pie, Inc. (N.D.Cal., Apr. 16, 1998, No. C 98-20064 JW) 1998 WL 388389, page *7, America Online, Inc. v. IMS (E.D.Va. 1998) 24 F.Supp.2d 548, 550-551, and America Online, Inc. v. LCGM, Inc. (E.D.Va. 1998) 46 F.Supp.2d 444, 451-452.
In each of these spamming cases, the plaintiff showed, or was prepared to show, some interference with the efficient functioning of its computer system. In CompuServe, the plaintiff ISP’s mail equipment monitor stated that mass UCE mailings, especially from nonexistent addresses such as those used by the defendant, placed “a tremendous burden” on the ISP’s equipment, using “disk space and draining] the processing power,” making those resources unavailable to serve subscribers. (CompuServe, supra, 962 F.Supp. at p. 1022.) Similarly, in Hotmail Corp. v. Van$ Money Pie, Inc., supra, 1998 WL 388389 at page *7, the court found the evidence supported a finding that the defendant’s mailings “fill[ed] up Hotmail’s computer storage space and threaten[ed] to damage Hotmail’s ability to service its legitimate customers.” America Online, Inc. v. IMS, decided on summary judgment, was deemed factually indistinguishable from CompuServe', the court observed that in both cases the plaintiffs “alleged that processing the bulk e-mail cost them time and money and burdened their equipment.” (America Online, Inc. v. IMS, supra, 24 F.Supp.2d at p. 550.) The same court, in America Online, Inc. v. LCGM, Inc., supra, 46 F.Supp.2d at page 452, simply followed CompuServe and its earlier America Online decision, quoting the former’s explanation that UCE burdened the computer’s processing power and memory.
Building on the spamming cases, in particular CompuServe, three even more recent district court decisions addressed whether unauthorized robotic data collection4 from a company’s publicly accessible Web site is a trespass on the company’s computer system. (eBay, Inc. v. Bidder’s Edge, Inc., supra, 100 F.Supp.2d at pp. 1069-1072 (eBay); Register.com, Inc. v. Verio, Inc. (S.D.N.Y. 2000) 126 F.Supp.2d 238, 248-251; Ticketmaster Corp. v. Tickets.com, Inc., supra, 2000 WL 1887522 at p. *4.) The two district courts that found such automated data collection to constitute a trespass relied, in part, on the deleterious impact this activity could have, especially if replicated by other searchers, on the functioning of a Web site’s computer equipment.
In the leading case, eBay, the defendant Bidder’s Edge (BE), operating an auction aggregation site, accessed the eBay Web site about 100,000 times *1355per day, accounting for between 1 and 2 percent of the information requests received by eBay and a slightly smaller percentage of the data transferred by eBay. (eBay, supra, 100 F.Supp.2d at pp. 1061, 1063.) The district court rejected eBay’s claim that it was entitled to injunctive relief because of the defendant’s unauthorized presence alone, or because of the incremental cost the defendant had imposed on operation of the eBay site (id. at pp. 1065-1066), but found sufficient proof of threatened harm in the potential for others to imitate the defendant’s activity: “If BE’s activity is allowed to continue unchecked, it would encourage other auction aggregators to engage in similar recursive searching of the eBay system such that eBay would suffer irreparable harm from reduced system performance, system unavailability, or data losses.” (Id. at p. 1066.) Again, in addressing the likelihood of eBay’s success on its trespass to chattels cause of action, the court held the evidence of injury to eBay’s computer system sufficient to support a preliminary injunction: “If the court were to hold otherwise, it would likely encourage other auction aggregators to crawl the eBay site, potentially to the point of denying effective access to eBay’s customers. If preliminary injunctive relief were denied, and other aggregators began to crawl the eBay site, there appears to be little doubt that the load on eBay’s computer system would qualify as a substantial impairment of condition or value.” (Id. at pp. 1071-1072.)
Another district court followed eBay on similar facts—a domain name registrar’s claim against a Web hosting and development site that robotically searched the registrar’s database of newly registered domain names in search of business leads—in Register.com, Inc. v. Verio, Inc., supra, 126 F.Supp.2d at pages 249-251. Although the plaintiff was unable to measure the burden the defendant’s searching had placed on its system (id. at pp. 249-250), the district court, quoting the declaration of one of the plaintiffs officers, found sufficient evidence of threatened harm to the system in the possibility the defendant’s activities would be copied by others: “ T believe that if Verio’s searching of Register.com’s WHOIS database were determined to be lawful, then every purveyor of Internet-based services would engage in similar conduct.’ ” (Id. at p. 250.) Like eBay, the court observed, Register.com had a legitimate fear “that its servers will be flooded by search robots.” (Id. at p. 251.)
In the third decision discussing robotic data collection as a trespass, Ticketmaster Corp. v. Tickets.com, Inc., supra, 2000 WL 1887522 (Ticketmaster), the court, distinguishing eBay, found insufficient evidence of harm to the chattel to constitute an actionable trespass: “A basic element of trespass to chattels must be physical harm to the chattel (not present here) or some obstruction of its basic function (in the court’s opinion not sufficiently *1356shown here). . . . The comparative use [by the defendant of the plaintiffs computer system] appears very small and there is no showing that the use interferes to any extent with the regular business of [the plaintiff], . . . Nor here is the specter of dozens or more parasites joining the fray, the cumulative total of which could affect the operation of [the plaintiff’s] business.” (Id. at p. *4, italics added.)
In the decisions so far reviewed, the defendant’s use of the plaintiffs computer system was held sufficient to support an action for trespass when it actually did, or threatened to, interfere with the intended functioning of the system, as by significantly reducing its available memory and processing power. In Ticketmaster, supra, 2000 WL 1887522, the one case where no such effect, actual or threatened, had been demonstrated, the court found insufficient evidence of harm to support a trespass action. These decisions do not persuade us to Intel’s position here, for Intel has demonstrated neither any appreciable effect on the operation of its computer system from Hamidi’s messages, nor any likelihood that Hamidi’s actions will be replicated by others if found not to constitute a trespass.
That Intel does not claim the type of functional impact that spammers and robots have been alleged to cause is not surprising in light of the differences between Hamidi’s activities and those of a commercial enterprise that uses sheer quantity of messages as its communications strategy. Though Hamidi sent thousands of copies of the same message on six occasions over 21 months, that number is minuscule compared to the amounts of mail sent by commercial operations. The individual advertisers sued in America Online, Inc. v. IMS, supra, 24 F.Supp.2d at page 549, and America Online, Inc. v. LCGM, Inc., supra, 46 F.Supp.2d at page 448, were alleged to have sent more than 60 million messages over 10 months and more than 92 million messages over seven months, respectively. Collectively, UCE has reportedly come to constitute about 45 percent of all e-mail. (Hansell, Internet Is Losing Ground in Battle Against Spam, N.Y. Times (Apr. 22, 2003) p. Al, col. 3.) The functional burden on Intel’s computers, or the cost in time to individual recipients, of receiving Hamidi’s occasional advocacy messages cannot be compared to the burdens and costs caused ISP’s and their customers by the ever-rising deluge of commercial e-mail.
Intel relies on language in the eBay decision suggesting that unauthorized use of another’s chattel is actionable even without any showing of injury: “Even if, as [defendant] BE argues, its searches use only a small amount of eBay’s computer system capacity, BE has nonetheless deprived eBay of the ability to use that portion of its personal property for its own purposes. The law recognizes no such right to use another’s personal property.” (eBay, *1357supra, 100 F.Supp.2d at p. 1071.) But as the eBay court went on immediately to find that the defendant’s conduct, if widely replicated, would likely impair the functioning of the plaintiffs system (id. at pp. 1071-1072), we do not read the quoted remarks as expressing, the court’s complete view of the issue. In isolation, moreover, they would not be a correct statement of California or general American law on this point. While one may have no right temporarily to use another’s personal property, such use is actionable as a trespass only if it “has proximately caused injury.” (Thrifty-Tel, supra, 46 Cal.App.4th at p. 1566.) “[I]n the absence of any actual damage the action will not lie.” (Prosser & Keeton, Torts, supra, § 14, p. 87.) Short of dispossession, personal injury, or physical damage (not present here), inter-meddling is actionable only if “the chattel is impaired as to its condition, quality, or value, or [f] . . . the possessor is deprived of the use of the chattel for a substantial time.” (Rest.2d Torts, § 218, pars, (b), (c).) In particular, an actionable deprivation of use “must be for a time so substantial that it is possible to estimate the loss caused thereby. A mere momentary or theoretical deprivation of use is not sufficient unless there is a dispossession . . . .” (Id., com. i, p. 423.) That Hamidi’s messages temporarily used some portion of the Intel computers’ processors or storage is, therefore, not enough; Intel must, but does not, demonstrate some measurable loss from the use of its computer system.5
In addition to impairment of system functionality, CompuServe and its progeny also refer to the ISP’s loss of business reputation and customer goodwill, resulting from the inconvenience and cost that spam causes to its members, as harm to the ISP’s legally protected interests in its personal property. (See CompuServe, supra, 962 F.Supp.2d at p. 1023; Hotmail Corp. v. Van$ Money Pie, Inc., supra, 1998 WL 388389 at p. *7; America Online, Inc. v. IMS, supra, 24 F.Supp.2d at p. 550.) Intel argues that its own interest in employee productivity, assertedly disrupted by Hamidi’s messages, is a comparable protected interest in its computer system. We disagree.
*1358Whether the economic injuries identified in CompuServe were properly considered injuries to the ISP’s possessory interest in its personal property, the type of property interest the tort is primarily intended to protect (see Rest.2d Torts, § 218 & com. e, pp. 421-422; Prosser & Keeton, Torts, supra, § 14, p. 87), has been questioned.6 “[T]he court broke the chain between the trespass and the harm, allowing indirect harms to CompuServe’s business interests—reputation, customer goodwill, and employee time—to count as harms to the chattel (the server).” (Quilter, The Continuing Expansion of Cyberspace Trespass to Chattels, supra, 17 Berkeley Tech. L.J. at pp. 429-430.) “[T]his move cuts trespass to chattels free from its moorings of dispossession or the equivalent, allowing the court free reign [sic] to hunt for ‘impairment.’” (Burk, The Trouble with Trespass (2000) 4 J. Small & Emerging Bus. L. 27, 35.) But even if the loss of goodwill identified in CompuServe were the type of injury that would give rise to a trespass to chattels claim under California law, Intel’s position would not follow, for Intel’s claimed injury has even less connection to its personal property than did CompuServe’s.
CompuServe’s customers were annoyed because the system was inundated with unsolicited commercial messages, making its use for personal communication more difficult and costly. (CompuServe, supra, 962 F.Supp. at p. 1023.) Their complaint, which allegedly led some to cancel their CompuServe service, was about the functioning of CompuServe’s electronic mail service. Intel’s workers, in contrast, were allegedly distracted from their work not because of the frequency or quantity of Hamidi’s messages, but because of assertions and opinions the messages conveyed. Intel’s complaint is thus about the contents of the messages rather than the functioning of the company’s e-mail system. Even accepting CompuServe’s economic injury rationale, therefore, Intel’s position represents a further extension of the trespass to chattels tort, fictionally recharacterizing the allegedly injurious effect of a communication’s contents on recipients as an impairment to the device which transmitted the message.
This theory of “impairment by content” (Burk, The Trouble with Trespass, supra, 4 J. Small & Emerging Bus. L. at p. 37) threatens to stretch trespass *1359law to cover injuries far afield from the harms to possession the tort evolved to protect. Intel’s theory would expand the tort of trespass to chattels to cover virtually any unconsented-to communication that, solely because of its content, is unwelcome to the recipient or intermediate transmitter. As the dissenting justice below explained, “ ‘Damage’ of this nature—the distraction of reading or listening to an unsolicited communication—is not within the scope of the injury against which the trespass-to-chattel tort protects, and indeed triviálizes it. After all, ‘[t]he property interest protected by the old action of trespass was that of possession; and this has continued to affect the character of the action.’ (Prosser & Keeton on Torts, supra, § 14, p. 87.) Reading an e-mail transmitted to equipment designed to receive it, in and of itself, does not affect the possessory interest in the equipment. [f] Indeed, if a chattel’s receipt of an electronic communication constitutes a trespass to that chattel, then not only are unsolicited telephone calls and faxes trespasses to chattel, but unwelcome radio waves and television signals also constitute a trespass to chattel every time the viewer inadvertently sees or hears the unwanted program.” We agree. While unwelcome communications, electronic or otherwise, can cause a variety of injuries to economic relations, reputation and emotions, those interests are protected by other branches of tort law; in order to address them, we need not create a fiction of injury to the communication system.
Nor may Intel appropriately assert a property interest in its employees’ time. “The Restatement test clearly speaks in the first instance to the impairment of the chattel. . . . But employees are not chattels (at least not in the legal sense of the term).” (Burk, The Trouble with Trespass, supra, 4 J. Small & Emerging Bus. L. at p. 36.) Whatever interest Intel may have in preventing its employees from receiving disruptive communications, it is not an interest in personal property, and trespass to chattels is therefore not an action that will lie to protect it. Nor, finally, can the fact Intel staff spent time attempting to block Hamidi’s messages be bootstrapped into an injury to Intel’s possessory interest in its computers. To quote, again, from the dissenting opinion in the Court of Appeal: “[I]t is circular to premise the damage element of a tort solely upon the steps taken to prevent the damage. Injury can only be established by the completed tort’s consequences, not by the cost of the steps taken to avoid the injury and prevent the tort; otherwise, we can create injury for every supposed tort.”
Intel connected its e-mail system to the Internet and permitted its employees to make use of this connection both for business and, to a reasonable extent, for their own purposes. In doing so, the company necessarily contemplated the employees’ receipt of unsolicited as well as solicited communications from other companies and individuals. That some communications *1360would, because of their contents, be unwelcome to Intel management was virtually inevitable. Hamidi did nothing but use the e-mail system for its intended purpose—to communicate with employees. The system worked as designed, delivering the messages without any physical or functional harm or disruption. These occasional transmissions cannot reasonably be viewed as impairing the quality or value of Intel’s computer system. We conclude, therefore, that Intel has not presented undisputed facts demonstrating an injury to its personal property, or to its legal interest in that property, that support, under California tort law, an action for trespass to chattels.
II. Proposed Extension of California Tort Law
We next consider whether California common law should be extended to cover, as a trespass to chattels, an otherwise harmless electronic communication whose contents are objectionable. We decline to so expand California law. Intel, of course, was not the recipient of Hamidi’s messages, but rather the owner and possessor of computer servers used to relay the messages, and it bases this tort action on that ownership and possession. The property rule proposed is a rigid one, under which the sender of an electronic message would be strictly liable to the owner of equipment through which the communication passes—here, Intel—for any consequential injury flowing from the contents of the communication. The arguments of amici curiae and academic writers on this topic, discussed below, leave us highly doubtful whether creation of such a rigid property rule would be wise.
Writing on behalf of several industry groups appearing as amici curiae, Professor Richard A. Epstein of the University of Chicago urges us to excuse the required showing of injury to personal property in cases of unauthorized electronic contact between computers, “extending the rules of trespass to real property to all interactive Web sites and servers.” The court is thus urged to recognize, for owners of a particular species of personal property, computer servers, the same interest in inviolability as is generally accorded a possessor of land. In effect, Professor Epstein suggests that a company’s server should be its castle, upon which any unauthorized intrusion, however harmless, is a trespass.
Epstein’s argument derives, in part, from the familiar metaphor of the Internet as a physical space, reflected in much of the language that has been used to describe it; “cyberspace,” “the information superhighway,” e-mail “addresses,” and the like. Of course, the Internet is also frequently called simply the “Net,” a term, Hamidi points out, “evoking a fisherman’s chattel.” A major component of the Internet is the World Wide “Web,” a *1361descriptive term suggesting neither personal nor real property, and “cyberspace” itself has come to be known by the oxymoronic phrase “virtual reality,” which would suggest that any real property “located” in “cyberspace” must be “virtually real” property. Metaphor is a two-edged sword.
Indeed, the metaphorical application of real property rules would not, by itself, transform a physically harmless electronic intrusion, on a computer server into a trespass. That is because, under California law, intangible intrusions on land, including electromagnetic transmissions, are not actionable as trespasses (though they may be as nuisances) unless they cause physical damage to the real property. (San Diego Gas & Electric Co. v. Superior Court (1996) 13 Cal.4th 893, 936-937 [55 Cal.Rptr.2d 724, 920 P.2d 669].) Since Intel does not claim Hamidi’s electronically transmitted messages physically damaged its servers, it could not prove a trespass to land even were we to treat the computers as a type of real property. Some further extension of the conceit would be required, under which the electronic signals Hamidi sent would be recast as tangible intruders, perhaps as tiny messengers rushing through the “hallways” of Intel’s computers and bursting out of employees’ computers to read them Hamidi’s missives. But such fictions promise more confusion than clarity in the law. (See eBay, supra, 100 F.Supp.2d at pp. 1065-1066 [rejecting eBay’s argument that the defendant’s automated data searches “should be thought of as equivalent to sending in an army of 100,000 robots a day to check the prices in a competitor’s store”].)
The plain fact is that computers, even those making up the Internet, are—like such older communications equipment as telephones and fax machines—personal property, not realty. Professor Epstein observes that “[although servers may be moved in real space, they cannot be moved in cyberspace,” because an Internet server must, to be useful, be accessible at a known address. But the same is true of the telephone: to be useful for incoming communication, the telephone must remain constantly linked to the same number (or, when the number is changed, the system must include some forwarding or notification capability, a qualification that also applies to computer addresses). Does this suggest that an unwelcome message delivered through a telephone or fax machine should be viewed as a trespass to a type of real property? We think not: As already discussed, the contents of a telephone communication may cause a variety of injuries and may be the basis for a variety of tort actions (e.g., defamation, intentional infliction of emotional distress, invasion of privacy), but the injuries are not to an *1362interest in property, much less real property, and the appropriate tort is not trespass.7
More substantively, Professor Epstein argues that a rule of computer server inviolability will, through the formation or extension of a market in computer-to-computer access, create “the right social result.” In most circumstances, he predicts, companies with computers on the Internet will continue to authorize transmission of information through e-mail, Web site searching, and page linking because they benefit by that open access. When a Web site owner does deny access to a particular sending, searching, or linking computer, a system of “simple one-on-one negotiations” will arise to provide the necessary individual licenses.
Other scholars are less optimistic about such a complete propertization of the Internet. Professor Mark Lemley of the University of California, Berkeley, writing on behalf of an amici curiae group of professors of intellectual property and computer law, observes that under a property rule of server inviolability, “each of the hundreds of millions of [Internet] users must get permission in advance from anyone with whom they want to communicate and anyone who owns a server through which their message may travel.” The consequence for e-mail could be a substantial reduction in the freedom of electronic communication, as the owner of each computer through which an electronic message passes could impose its own limitations on message content or source. As Professor Dan Hunter of the University of Pennsylvania asks rhetorically: “Does this mean that one must read the ‘Terms of Acceptable Email Usage’ of every email system that one emails in the course of an ordinary day? If the University of Pennsylvania had a policy *1363that sending a joke by email would be an unauthorized use of its system, then under the logic of [the lower court decision in this case], you would commit ‘trespass’ if you emailed mea. . . cartoon.” (Hunter, Cyberspace as Place and the Tragedy of the Digital Anticommons (2003) 91 Cal. L.Rev. 439, 508-509.)
Web site linking, Professor Lemley further observes, “would exist at the sufferance of the linked-to party, because a Web user who followed a ‘disapproved’ link would be trespassing on the plaintiffs server, just as sending an e-mail is trespass under the [lower] court’s theory.” Another writer warns that “[c]yber-trespass theory will curtail the free flow of price and product information on the Internet by allowing website owners to tightly control who and what may enter and make use of the information housed on its Internet site.” (Chang, Bidding on Trespass: eBay, Inc. v. Bidder’s Edge, Inc. and the Abuse of Trespass Theory in Cyberspace Law (2001) 29 AIPLA Q.J. 445, 459.) A leading scholar of Internet law and policy, Professor Lawrence Lessig of Stanford University, has criticized Professor Epstein’s theory of the computer server as quasi-real property, previously put forward in the eBay case (eBay, supra, 100 F.Supp.2d 1058), on the ground that it ignores the costs to society in the loss of network benefits: “eBay benefits greatly from a network that is open and where access is free. It is this general feature of the Net that makes the Net so valuable to users and a source of great innovation. And to the extent that individual sites begin to impose their own rules of exclusion, the value of the network as a network declines. If machines must negotiate before entering any individual site, then the costs of using the network climb.” (Lessig, The Future of Ideas: The Fate of the Commons in a Connected World (2001) p. 171; see also Hunter, Cyberspace as Place and the Tragedy of the Digital Anticommons, supra, 91 Cal. L.Rev. at p. 512 [“If we continue to mark out anticommons claims in cyberspace, not only will we preclude better, more innovative uses of cyberspace resources, but we will lose sight of what might be possible”].)
We discuss this debate among the amici curiae and academic writers only to note its existence and contours, not to attempt its resolution. Creating an absolute property right to exclude undesired communications from one’s e-mail and Web servers might help force spammers to internalize the costs they impose on ISP’s and their customers. But such a property rule might also create substantial new costs, to e-mail and e-commerce users and to society generally, in lost ease and openness of communication and in lost network benefits. In light of the unresolved controversy, we would be acting rashly to adopt a rule treating computer servers as real property for purposes of trespass law.
*1364The Legislature has already adopted detailed regulations governing UCE. (Bus. & Prof. Code, §§ 17538.4, 17538.45; see generally Ferguson v. Friendfinders, Inc., supra, 94 Cal.App.4th 1255.) It may see fit in the future also to regulate noncommercial e-mail, such as that sent by Hamidi, or other kinds of unwanted contact between computers on the Internet, such as that alleged in eBay, supra, 100 F.Supp.2d 1058. But we are not persuaded that these perceived problems call at present for judicial creation of a rigid property rule of computer server inviolability. We therefore decline to create an exception, covering Hamidi’s unwanted electronic messages to Intel employees, to the general rule that a trespass to chattels is not actionable if it does not involve actual or threatened injury to the personal property or to the possessor’s legally protected interest in the personal property. No such injury having been shown on the undisputed facts, Intel was not entitled to summary judgment in its favor.
III. Constitutional Considerations
Because we conclude no trespass to chattels was shown on the summary judgment record, making the injunction improper on common law grounds, we need not address at length the dissenters’ constitutional arguments. A few clarifications are nonetheless in order.
Justice Mosk asserts that this case involves only “a private entity seeking to enforce private rights against trespass.” (Dis. opn. of Mosk, J., post, at p. 1395.) But the injunction here was issued by a state court. While a private refusal to transmit another’s electronic speech generally does not implicate the First Amendment, because no governmental action is involved (see Cyber Promotions, Inc. v. America Online, Inc. (E.D.Pa. 1996) 948 F.Supp. 436, 441-445 [spammer could not force private ISP to carry its messages]), the use of government power, whether in enforcement of a statute or ordinance or by an award of damages or an injunction in a private lawsuit, is state action that must comply with First Amendment limits. (Cohen v. Cowles Media Co. (1991) 501 U.S. 663, 668 [111 S.Ct. 2513, 2517, 115 L.Ed.2d 586]; NAACP v. Claiborne Hardware Co. (1982) 458 U.S. 886, 916, in. 51 [102 S.Ct. 3409, 3427, 73 L.Ed.2d 1215]; New York Times v. Sullivan (1964) 376 U.S. 254, 265 [84 S.Ct. 710, 718, 11 L.Ed.2d 686, 95 A.L.R.2d 1412].) Nor does the nonexistence of a “constitutional right to trespass” (dis. opn. of Mosk, J., post, at p. 1395) make an injunction in this case per se valid. Unlike, for example, the trespasser-to-land defendant in Church of Christ in Hollywood v. Superior Court (2002) 99 Cal.App.4th 1244 [121 Cal.Rptr.2d 810], Hamidi himself had no tangible presence on Intel property, instead speaking from his own home through his *1365computer. He no more invaded Intel’s property than does a protester holding a sign or shouting through a bullhorn outside corporate headquarters, posting a letter through the mail, or telephoning to complain of a corporate practice. (See Madsen v. Women’s Health Center (1994) 512 U.S. 753, 765 [114 S.Ct. 2516, 2525, 129 L.Ed.2d 593] [injunctions restraining such speakers must “burden no more speech than necessary to serve a significant government interest”].)8
Justice Brown relies upon a constitutional “right not to listen,” rooted in the listener’s “personal autonomy” (dis. opn. of Brown, J., post, at p. 1374), as compelling a remedy against Hamidi’s messages, which she asserts were sent to “unwilling” listeners (id. at p. 1369). Even assuming a corporate entity could under some circumstances claim such a personal right, here the intended and actual recipients of Hamidi’s messages were individual Intel employees, rather than Intel itself. The record contains no evidence Hamidi sent messages to any employee who notified him such messages were unwelcome. In any event, such evidence would, under the dissent’s rationale of a right not to listen, support only a narrow injunction aimed at protecting individual recipients who gave notice of their rejection. (See Bolger v. Youngs Drug Products Corp. (1983) 463 U.S. 60, 72 [103 S.Ct. 2875, 2883, 77 L.Ed.2d 469] [government may not act on behalf of all addressees by generally prohibiting mailing of materials related to contraception, where those recipients who may be offended can simply ignore and discard the materials]; Martin v. City of Struthers (1943) 319 U.S. 141, 144 [63 S.Ct. 862, 863, 87 L.Ed. 1313] [anti-canvassing ordinance improperly “substitutes the judgment of the community for the judgment of the individual householder”]; cf. Rowan v. U.S. Post Office Dept. (1970) 397 U.S. 728, 736 [90 S.Ct. 1484, 1490, 25 L.Ed.2d 736] [“householder” may exercise “individual autonomy” by refusing delivery of offensive mail].) The principle of a right not to listen, founded in personal autonomy, cannot justify the sweeping injunction issued here against all communication to Intel addresses, for such a right, logically, can be exercised only by, or at the behest of, the recipient himself or herself.
*1366Disposition
The judgment of the Court of Appeal is reversed.
Kennard, J., Moreno, J., and Perren, J.,* concurred.
To the extent, therefore, that Justice Mosk suggests Hamidi breached the security of Intel’s internal computer network by “circumventing]” Intel’s “security measures” and entering the company’s “intranet” (dis. opn. of Mosk, J., post, at p. 1386), the evidence does not support such an implication. An “intranet” is “a network based on TCP/IP protocols (an internet) belonging to an organization, usually a corporation, accessible only by the organization’s members, employees, or others with authorization.” (<http://www.webopedia.eom/TERM/i/ intranet.html> [as of June 30, 2003].) Hamidi used only a part of Intel’s computer network accessible to outsiders.
For the first time, in this court, Intel argues Hamidi’s appeal is moot because, as FACE-Intel’s agent, Hamidi is bound, whatever the outcome of his own appeal, by the unappealed injunction against FACE-Intel. But as Hamidi points out in response, he could avoid the unappealed injunction simply by resigning from FACE-Intel; his own appeal is therefore not moot.
We grant both parties’ requests for notice of legislative history materials relating to California laws on spam and on injunctions in labor dispute cases. Hamidi’s further request for notice of the “undisputed” fact that “e-mail messages that travel into computer equipment consist of electromagnetic waves” is denied as irrelevant.
Data search and collection robots, also known as “Web bots” or “spiders,” are programs designed to rapidly search numerous Web pages or sites, collecting, retrieving, and indexing information from these pages. Their uses include creation of searchable databases, Web catalogues and comparison shopping services. {eBay, Inc. v. Bidder’s Edge, Inc. (N.D.Cal. 2000) 100 F.Supp.2d Í058, 1060-1061; O’Rourke, Property Rights and Competition on the Internet: In Search of an Appropriate Analogy (2001) 16 Berkeley Tech. L.J. 561, 570-571; Quilter, The Continuing Expansion of Cyberspace Trespass to Chattels (2002) 17 Berkeley Tech. L.J. 421, 423-424.)
In the most recent decision relied upon by Intel, Oyster Software, Inc. v. Forms Processing, Inc. (N.D.Cal., Dec. 6, 2001, No. C-00-0724 JCS) 2001 WL 1736382, pages *12-*13, a federal magistrate judge incorrectly read eBay as establishing, under California law, that mere unauthorized use of another’s computer system constitutes an actionable trespass. The plaintiff accused the defendant, a business competitor, of copying the metatags (code describing the contents of a Web site to a search engine) from the plaintiffs Web site, resulting in diversion of potential customers for the plaintiffs services. (Id. at pp. *l-*2.) With regard to the plaintiffs trespass claim (the plaintiff also pleaded causes of action for, inter alia, misappropriation, copyright and trademark infringement), the magistrate judge concluded that eBay imposed no requirement of actual damage and that the defendant’s conduct was sufficient to establish a trespass “simply because [it] amounted to ‘use’ of Plaintiffs computer.” (Id. at p. *13.) But as just explained, we do not read eBay, supra, 100 F.Supp.2d 1058, as holding that the actual injury requirement may be dispensed with, and such a suggestion would, in any event, be erroneous as a statement of California law.
In support of its reasoning, the CompuServe court cited paragraph (d) of section 218 of the Restatement Second of Torts, which refers to harm “to some person or thing in which the possessor has a legally protected interest.” As the comment to this paragraph explains, however, it is intended to cover personal injury to the possessor or another person in whom the possessor has a legal interest, or injury to “other chattel or land” in which the possessor of the chattel subject to the trespass has a legal interest. (Rest.2d Torts, § 218, com. j, p. 423.) No personal injury was claimed either in CompuServe or in the case at bar, and neither the lost goodwill in CompuServe nor the loss of employee efficiency claimed in the present case is chattel or land.
The tort law discussion in Justice- Brown’s dissenting opinion similarly suffers from an overreliance on metaphor and analogy. Attempting to find an actionable trespass, Justice Brown analyzes Intel’s e-mail system as comparable to the exterior of an automobile (dis. opn. of Brown, J., post, at p. 1367), a plot of land (id. at p. 1377), the interior of an automobile (id. at p. 1379), a toothbrush (id. p. at 1382), a head of livestock (id. at pp. 1382-1383), and a mooring buoy (id. at pp. 1383-1384), while Hamidi is characterized as a vandal damaging a school building (id. at p. 1381) or a prankster unplugging and moving employees’ computers (id. at p. 1383). These colorful analogies tend to obscure the plain fact that this case involves communications equipment, used by defendant to communicate. Intel’s e-mail system was equipment designed for speedy communication between employees and the outside world; Hamidi communicated with Intel employees over that system in a manner entirely consistent with its design; and Intel objected not because of an offense against the integrity or dignity of its computers, but because the communications themselves affected employee-recipients in a manner Intel found undesirable. The proposal that we extend trespass to chattels to cover any communication that the owner of the communications equipment considers annoying or distracting raises, moreover, concerns about control over the flow of information and views that would not be presented by, for example, an injunction against chasing another’s cattle or sleeping in her car.
Justice Brown would distinguish Madsen v. Women's Health Center, on the ground that the operators of the health center in that case would not have been entitled to “drive[] [the protesters] from the public streets,” whereas Intel was entitled to block Hamidi’s messages as best it could. (Dis. opn. of Brown, J., post, at p. 1370, fh. 1.) But the health center operators were entitled to block protesters’ messages—as best they could—by closing windows and pulling blinds. That a property owner may take physical measures to prevent the transmission of others’ speech into or across the property does not imply that a court order enjoining the speech is not subject to constitutional limitations.
Associate Justice of the Court of Appeal, Second Appellate District, Division Six, assigned by the Chief Justice pursuant to article VI, section 6 of the California Constitution.