We plumb the depths of the immunity provided by section 230 of the Communications Decency Act of 1996 (“CDA”).
Facts1
Defendant Roommate.com, LLC (“Roommate”) operates a website designed to match people renting out spare rooms with people looking for a place to live.2 At the time of the district court’s disposition, Roommate’s website featured approximately 150,000 active listings and received around a million page views a day. Roommate seeks to profit by collecting revenue from advertisers and subscribers.
Before subscribers can search listings or post3 housing opportunities on Roommate’s website, they must create profiles, a process that requires them to answer a series of questions. In addition to requesting basic information — such as name, location and email address — Roommate requires each subscriber to disclose his sex, sexual orientation and whether he would bring children to a household. Each subscriber must also describe his preferences in roommates with respect to the same three criteria: sex, sexual orientation and whether they will bring children to the household. The site also encourages subscribers to provide “Additional Comments” describing themselves and their desired roommate in an open-ended essay. After a new subscriber completes the application, Roommate assembles his answers into a “profile page.” The profile page *1162displays the subscriber’s pseudonym, his description and his preferences, as divulged through answers to Roommate’s questions.
Subscribers can choose between two levels of service: Those using the site’s free service level can create their own personal profile page, search the profiles of others and send personal email messages. They can also receive periodic emails from Roommate, informing them of available housing opportunities matching their preferences. Subscribers who pay a monthly fee also gain the ability to read emails from other users, and to view other subscribers’ “Additional Comments.”
The Fair Housing Councils of the San Fernando Valley and San Diego (“Councils”) sued Roommate in federal court, alleging that Roommate’s business violates the federal Fair Housing Act (“FHA”), 42 U.S.C. § 3601 et seq., and California housing discrimination laws.4 Councils claim that Roommate is effectively a housing broker doing online what it may not lawfully do off-line. The district court held that Roommate is immune under section 230 of the CDA, 47 U.S.C. § 230(c), and dismissed the federal claims without considering whether Roommate’s actions violated the FHA. The court then declined to exercise supplemental jurisdiction over the state law claims. Councils appeal the dismissal of the FHA claim and Roommate cross-appeals the denial of attorneys’ fees.
Analysis
Section 230 of the CDA5 immunizes providers of interactive computer services 6 against liability arising from content created by third parties: “No provider ... of an interactive computer service shall be treated as the publisher or speaker of any information provided by another information content provider.” 47 U.S.C. § 230(c).7 This grant of immunity applies only if the interactive computer service provider is not also an “information content provider,” which is defined as someone who is “responsible, in whole or in part, for the creation or development of’ the offending content. Id. § 230(f)(3).
A website operator can be both a service provider and a content provider: If it passively displays content that is created entirely by third parties, then it is only a service provider with respect to that content. But as to content that it creates itself, or is “responsible, in whole or in part” for creating or developing, the website is also a content provider. Thus, a website may be immune from liability for *1163some of the content it displays to the public but be subject to liability for other content.8
Section 230 was prompted by a state court case holding Prodigy9 responsible for a libelous message posted on one of its financial message boards.10 See Stratton Oakmont, Inc. v. Prodigy Servs. Co., 1995 WL 323710 (N.Y.Sup.Ct. May 24, 1995) (unpublished). The court there found that Prodigy had become a “publisher” under state law because it voluntarily deleted some messages from its message boards “on the basis of offensiveness and ‘bad taste,’ ” and was therefore legally responsible for the content of defamatory messages that it failed to delete. Id. at *4. The Stratton Oakmont court reasoned that Prodigy’s decision to perform some voluntary self-policing made it akin to a newspaper publisher, and thus responsible for messages on its bulletin board that defamed third parties. The court distinguished Prodigy from CompuServe,11 which had been released from liability in a similar defamation case because CompuServe “had no opportunity to review the contents of the publication at issue before it was uploaded into CompuServe’s computer banks.” Id.; see Cubby, Inc. v. CompuServe, Inc., 776 F.Supp. 135, 140 (S.D.N.Y.1991). Under the reasoning of Stratton Oakmont, online service providers that voluntarily filter some messages become liable for all messages transmitted, whereas providers that bury their heads in the sand and ignore problematic posts altogether escape liability. Prodigy claimed that the “sheer volume” of message board postings it received — at the time, over 60,-000 a day — made manual review of every message impossible; thus, if it were forced to choose between taking responsibility for all messages and deleting no messages at all, it would have to choose the latter course. Stratton Oakmont, 1995 WL 323710 at *3.
In passing section 230, Congress sought to spare interactive computer services this grim choice by allowing them to perform some editing on user-generated content without thereby becoming liable for all defamatory or otherwise unlawful messages that they didn’t edit or delete. In other words, Congress sought to immunize the removal of user-generated content, not the creation of content: “[Sjection [230] provides ‘Good Samaritan’ protections from civil liability for providers ... of an interactive computer service for actions to restrict ... access to objectionable online material. One of the specific purposes of this section is to overrule Stratton-Oakmont [sic] v. Prodigy and any other similar decisions which have treated such providers ... as publishers or speakers of content that is not their own because they have restricted access to objectionable material.” H.R.Rep. No. 104-58 (1996) (Conf.Rep.), as reprinted in 1996 U.S.C.C.A.N. 10 (emphasis added).12 Indeed, the section is titled “Protection for ‘good Samaritan’ blocking and *1164screening of offensive material” and, as the Seventh Circuit recently held, the substance of section 230(c) can and should be interpreted consistent with its caption. Chicago Lawyers’ Committee for Civil Rights Under Law, Inc. v. craigslist, Inc., 519 F.3d 666,-(7th Cir.2008) (quoting Doe v. GTE Corp., 347 F.3d 655, 659-60 (7th Cir.2003)).
With this backdrop in mind, we examine three specific functions performed by Roommate that are alleged to violate the Fair Housing Act and California law.
1. Councils first argue that the questions Roommate poses to prospective subscribers during the registration process violate the Fair Housing Act and the analogous California law. Councils allege that requiring subscribers to disclose their sex, family status and sexual orientation “indicates” an intent to discriminate against them, and thus runs afoul of both the FHA and state law.13
Roommate created the questions and choice of answers, and designed its website registration process around them. Therefore, Roommate is undoubtedly the “information content provider” as to the questions and can claim no immunity for posting them on its website, or for forcing subscribers to answer them as a condition of using its services.
Here, we must determine whether Roommate has immunity under the CDA because Councils have at least a plausible claim that Roommate violated state and federal law by merely posing the questions. We need not decide whether any of Roommate’s questions actually violate the Fair Housing Act or California law, or whether they are protected by the First Amendment or other constitutional guarantees, see craigslist, at 1166-67; we leave those issues for the district court on remand. Rather, we examine the scope of plaintiffs’ substantive claims only insofar as necessary to determine whether section 230 immunity applies. However, we note that asking questions certainly can violate the Fair Housing Act and analogous laws in the physical world.14 For example, a real estate broker may not inquire as to the race of a prospective buyer, and an employer may not inquire as to the religion of a prospective employee. If such questions are unlawful when posed face-to-face or by telephone, they don’t magically become lawful when asked electronically online. The Communications Decency Act was not meant to create a lawless no-man’s-land on the Internet.15
*1165Councils also claim that requiring subscribers to answer the questions as a condition of using Roommate’s services unlawfully “cause[s]” subscribers to make a “statement ... with respect to the sale or rental of a dwelling that indicates [a] preference, limitation, or discrimination,” in violation of 42 U.S.C. § 3604(c). The CDA does not grant immunity for inducing third parties to express illegal preferences. Roommate’s own acts — posting the questionnaire and requiring answers to it — are entirely its doing and thus section 230 of the CDA does not apply to them. Roommate is entitled to no immunity.16
2. Councils also charge that Roommate’s development and display of subscribers’ discriminatory preferences is unlawful. Roommate publishes a “profile page” for each subscriber on its website. The page describes the client’s personal information — such as his sex, sexual orientation and whether he has children — as well as the attributes of the housing situation he seeks. The content of these pages is drawn directly from the registration process: For example, Roommate requires subscribers to specify, using a drop-down menu17 provided by Roommate, whether they are “Male” or “Female” and then displays that information on the profile page. Roommate also requires subscribers who are listing available housing to disclose whether there are currently “Straight male(s),” “Gay male(s),” “Straight female(s)” or “Lesbian(s)” living in the dwelling. Subscribers who are seeking housing must make a selection from a drop-down menu, again provided by Roommate, to indicate whether they are willing to live with “Straight or gay” males, only with “Straight” males, only with “Gay” males or with “No males.” Similarly, Roommate requires subscribers listing housing to disclose whether there are “Children present” or “Children not present” and requires housing seekers to say “I will live with children” or “I will not live with children.” Roommate then displays these answers, along with other information, on the subscriber’s profile page. This information is obviously included to help subscribers decide which housing opportunities to pursue and which to bypass. In addition, Roommate itself uses this information to channel subscribers away from listings where the individual offering housing has expressed preferences that aren’t compatible with the subscriber’s answers.
The dissent tilts at windmills when it shows, quite convincingly, that Roommate’s subscribers are information content providers who create the profiles by picking among options and providing their own answers. Dissent at 1180-82. There is no disagreement on this point. But, the fact that users are information content providers does not preclude Roommate from also being an information content provider by helping “develop” at least “in part” the information in the profiles. As we explained in Batzel, the party responsible for putting information online may be subject to liability, even if the information originated with a user. See Batzel v. Smith, 333 F.3d 1018,1033 (9th Cir.2003).18
*1166Here, the part of the profile that is alleged to offend the Fair Housing Act and state housing discrimination laws — the information about sex, family status and sexual orientation — is provided by subscribers in response to Roommate’s questions, which they cannot refuse to answer if they want to use defendant’s services. By requiring subscribers to provide the information as a condition of accessing its service, and by providing a limited set of prepopulated answers, Roommate becomes much more than a passive transmitter of information provided by others; it becomes the developer, at least in part, of that information. And section 230 provides immunity only if the interactive computer service does not “creat[e] or develop[ ]” the information “in whole or in part.” See 47 U.S.C. § 230(f)(3).
Our dissenting colleague takes a much narrower view of what it means to “develop” information online, and concludes that Roommate does not develop the information because “[a]ll Roommate does is to provide a form with options for standardized answers.” Dissent at 1182. But Roommate does much more than provide options. To begin with, it asks discriminatory questions that even the dissent grudgingly admits are not entitled to CDA immunity. Dissent at 1177 n. 5. The FHA makes it unlawful to ask certain discriminatory questions for a very good reason: Unlawful questions solicit (a.k.a. “develop”) unlawful answers. Not only does Roommate ask these questions, Roommate makes answering the discriminatory questions a condition of doing business. This is no different from a real estate broker in real life saying, “Tell me whether you’re Jewish or you can find yourself another broker.” When a business enterprise extracts such information from potential customers as a condition of accepting them as clients, it is no stretch to say that the enterprise is responsible, at least in part, for developing that information. For the dissent to claim that the information in such circumstances is “created solely by” the customer, and that the business has not helped in the least to develop it, Dissent at 1181-82, strains both credulity and English.19
Roommate also argues that it is not responsible for the information on the profile page because it is each subscriber’s action that leads to publication of his particular profile — in other words, the user pushes the last button or takes the last act before publication. We are not convinced that this is even true,20 but don’t see why it matters anyway. The projectionist in the theater may push the last button before a film is displayed on the screen, but surely this doesn’t make him the sole producer of *1167the movie. By any reasonable use of the English language, Roommate is “responsible” at least “in part” for each subscriber’s profile page, because every such page is a collaborative effort between Roommate and the subscriber.
Similarly, Roommate is not entitled to CDA immunity for the operation of its search system, which filters listings, or of its email notification system, which directs emails to subscribers according to discriminatory criteria.21 Roommate designed its search system so it would steer users based on the preferences and personal characteristics that Roommate itself forces subscribers to disclose. If Roommate has no immunity for asking the discriminatory questions, as we concluded above, see pp. 1164-65 supra, it can certainly have no immunity for using the answers to the unlawful questions to limit who has access to housing.
For example, a subscriber who self-identifies as a “Gay male” will not receive email notifications of new housing opportunities supplied by owners who limit the universe of acceptable tenants to “Straight male(s),” “Straight female(s)” and “Lesbian(s).” Similarly, subscribers with children will not be notified of new listings where the owner specifies “no children.” Councils charge that limiting the information a subscriber can access based on that subscriber’s protected status violates the Fair Housing Act and state housing discrimination laws. It is, Councils allege, no different from a real estate broker saying to a client: “Sorry, sir, but I can’t show you any listings on this block because you are [gay/female/black/a parent].” If such screening is prohibited when practiced in person or by telephone, we see no reason why Congress would have wanted to make it lawful to profit from it online.
Roommate’s search function is similarly designed to steer users based on discriminatory criteria. Roommate’s search engine thus differs materially from generic search engines such as Google, Yahoo! and MSN Live Search, in that Roommate designed its system to use allegedly unlawful criteria so as to limit the results of each search, and to force users to participate in its discriminatory process. In other words, Councils allege that Roommate’s search is designed to make it more difficult or impossible for individuals with certain protected characteristics to find housing— something the law prohibits. By contrast, ordinary search engines do not use unlawful criteria to limit the scope of searches conducted on them, nor are they designed to achieve illegal ends — as Roommate’s search function is alleged to do here. Therefore, such search engines play no part in the “development” of any unlawful searches. See 47 U.S.C. § 230(f)(3).
It’s true that the broadest sense of the term “develop” could include the functions of an ordinary search engine- — indeed, just about any function performed by a website. But to read the term so broadly would defeat the purposes of section 230 by swallowing up every bit of the immunity that the section otherwise provides. At the same time, reading the exception for co-developers as applying only to content that originates entirely with the website — as the dissent would seem to suggest — ignores the words “development ... in part” in the statutory passage “creation or development in whole or in part.” 47 U.S.C. § 230(f)(3) (emphasis added). We believe that both the immunity for passive conduits and the exception for co-developers must be given their proper scope and, to that end, we interpret the term “development” as referring not mere*1168ly to augmenting the content generally, but to materially contributing to its alleged unlawfulness. In other words, a website helps to develop unlawful content, and thus falls within the exception to section 230, if it contributes materially to the alleged illegality of the conduct.
The dissent accuses us of “rac[ing] past the plain language of the statute,” dissent at 1185, but we clearly do pay close attention to the statutory language, particularly the word “develop,” which we spend many pages exploring. The dissent may disagree with our definition of the term, which is entirely fair, but surely our dissenting colleague is mistaken in suggesting we ignore the term. Nor is the statutory language quite as plain as the dissent would have it. Dissent at 1183-85. Quoting selectively from the dictionary, the dissent comes up with an exceedingly narrow definition of this rather complex and multi faceted term.22 Dissent at 1184 (defining development as “gradual advance or growth through progressive changes”) (quoting Webster’s Third New International Dictionary 618 (2002)). The dissent does not pause to consider how such a definition could apply to website content at all, as it excludes the kinds of swift and disorderly changes that are the hallmark of growth on the Internet. Had our dissenting colleague looked just a few lines lower on the same page of the same edition of the same dictionary, she would have found another definition of “development” that is far more suitable to the context in which we operate: “making usable or available.” Id. The dissent does not explain why the definition it has chosen reflects the statute’s “plain meaning,” while the ones it bypasses do not.
More fundamentally, the dissent does nothing at all to grapple with the difficult statutory problem posed by the fact that section 230(c) uses both “create” and “develop” as separate bases for loss of immunity. Everything that the dissent includes within its cramped definition of “development” fits just as easily within the definition of “creation” — which renders the term “development” superfluous. The dissent makes no attempt to explain or offer examples as to how its interpretation of the statute leaves room for “development” as a separate basis for a website to lose its immunity, yet we are advised by the Supreme Court that we must give meaning to all statutory terms, avoiding redundancy or duplication wherever possible. See Park N Fly, Inc. v. Dollar Park & Fly, Inc., 469 U.S. 189, 197, 105 S.Ct. 658, 83 L.Ed.2d 582 (1985).
While content to pluck the “plain meaning” of the statute from a dictionary definition that predates the Internet by decades, compare Webster’s Third New International Dictionary 618 (1963) with Webster’s Third New International Dictionary 618 (2002) (both containing “gradual advance or growth through progressive changes”), the dissent overlooks the far more relevant definition of “[web] content development” in Wikipedia: “the process of researching, writing, gathering, organizing and editing information for publication on web sites.” Wikipedia, Content Development (Web), http://en.wikipedia. org/w/index.php?title=Content — development — -web. & oldid=188219503 (last visited Mar. 19, 2008). Our interpretation of “development” is entirely in line with the context-appropriate meaning of the term, *1169and easily fits the activities Roommate engages in.
In an abundance of caution, and to avoid the kind of misunderstanding the dissent seems to encourage, we offer a few examples to elucidate what does and does not amount to “development” under section 230 of the Communications Decency Act: If an individual uses an ordinary search engine to query for a “white roommate,” the search engine has not contributed to any alleged unlawfulness in the individual’s conduct; providing neutral tools to carry out what may be unlawful or illicit searches does not amount to “development” for purposes of the immunity exception. A dating website that requires users to enter their sex, race, religion and marital status through drop-down menus, and that provides means for users to search along the same lines, retains its CDA immunity insofar as it does not contribute to any alleged illegality;23 this immunity is retained even if the website is sued for libel based on these characteristics because the website would not have contributed materially to any alleged defamation. Similarly, a housing website that allows users to specify whether they will or will not receive emails by means of user-defined, criteria might help some users exclude email from other users of a particular race or sex. However, that website would be immune, so long as it does not require the use of discriminatory criteria. A website operator who edits user-created content — such as by correcting spelling, removing obscenity or trimming for length — retains his immunity for any illegality in the user-created content, provided that the edits are unrelated to the illegality. However, a website operator who edits in a manner that contributes to the alleged illegality — such as by removing the word “not” from a user’s message reading “[Name] did not steal the artwork” in order to transform an innocent message into a libelous one — is directly involved in the alleged illegality and thus not immune.24
Here, Roommate’s connection to the discriminatory filtering process is direct and palpable: Roommate designed its search and email systems to limit the listings available to subscribers based on sex, sexual orientation and presence of children.25 Roommate selected the criteria used to hide listings, and Councils allege that the act of hiding certain listings is itself unlawful under the Fair Housing Act, which prohibits brokers from steering clients in accordance with discriminatory *1170preferences.26 We need not decide the merits of Councils’ claim to hold that Roommate is sufficiently involved with the design and operation of the search and email systems — which are engineered to limit access to housing on the basis of the protected characteristics elicited by the registration process — so as to forfeit any immunity to which it was otherwise entitled under section 230.
Roommate’s situation stands in stark contrast to Stratton Oakmont, the case Congress sought to reverse through passage of section 230. There, defendant Prodigy was held liable for a user’s unsolicited message because it attempted to remove some problematic content from its website, but didn’t remove enough. Here, Roommate is not being sued for removing some harmful messages while failing to remove others; instead, it is being sued for the predictable consequences of creating a website designed to solicit and enforce housing preferences that are alleged to be illegal.
We take this opportunity to clarify two of our previous rulings regarding the scope of section 230 immunity. Today’s holding sheds additional light on Batzel v. Smith, 333 F.3d 1018 (9th Cir.2003). There, the editor of an email newsletter received a tip about some artwork, which the tipster falsely alleged to be stolen. The newsletter editor incorporated the tipster’s email into the next issue of his newsletter and added a short headnote, which he then emailed to his subscribers.27 The art owner sued for libel and a split panel held the newsletter editor to be immune under section 230 of the CD A.28
Our opinion is entirely consistent with that part of Batzel which holds that an editor’s minor changes to the spelling, grammar and length of third-party content do not strip him of section 230 immunity. None of those changes contributed to the libelousness of the message, so they do not add up to “development” as we interpret the term. See pp. 1167-69 supra. Batzel went on to hold that the editor could be liable for selecting the tipster’s email for inclusion in the newsletter, depending on whether or not the tipster had tendered the piece to the editor for posting online, and remanded for a determination of that issue. Batzel, 333 F.3d at 1035.
The distinction drawn by Batzel anticipated the approach we take today. As Batzel explained, if the tipster tendered the material for posting online, then the editor’s job was, essentially, to determine whether or not to prevent its posting— precisely the kind of activity for which section 230 was meant to provide immunity.29 And any activity that can be boiled *1171down to deciding whether to exclude material that third parties seek to post online is perforce immune under section 230. See p. 1171-72 & n. 32 infra. But if the editor publishes material that he does not believe was tendered to him for posting online, then he is the one making the affirmative decision to publish, and so he contributes materially to its allegedly unlawful dissemination. He is thus properly deemed a developer and not entitled to CDA immunity. See Batzel, 333 F.3d at 1033.30
We must also clarify the reasoning undergirding our holding in Carafano v. Metrosplash.com, Inc., 339 F.3d 1119 (9th Cir.2003), as we used language there that was unduly broad. In Carafano, an unknown prankster impersonating actress Christianne Carafano created a profile for her on an online dating site. The profile included Carafano’s home address and suggested that she was looking for an unconventional liaison. When Carafano received threatening phone calls, she sued the dating site for publishing the unauthorized profile. The site asserted immunity under section 230. We correctly held that the website was immune, but incorrectly suggested that it could never be liable because “no [dating] profile has any content until a user actively creates it.” Id. at 1124. As we explain above, see pp. 1165— 70 supra, even if the data are supplied by third parties, a website operator may still contribute to the content’s illegality and thus be liable as a developer.31 Providing immunity every time a website uses data initially obtained from third parties would eviscerate the exception to section 230 for “developing]” unlawful content “in whole or in part.” 47 U.S.C. § 230(f)(3).
We believe a more plausible rationale for the unquestionably correct result in Carafano is this: The allegedly libelous content there — the false implication that Carafano was unchaste — was created and developed entirely by the malevolent user, without prompting or help from the website operator. To be sure, the website provided neutral tools, which the anonymous dastard used to publish the libel, but the website did absolutely nothing to encourage the posting of defamatory content — indeed, the defamatory posting was contrary to the website’s express policies. The claim against the website was, in effect, that it failed to review each user-created profile to ensure that it wasn’t defamatory. That is precisely the kind of *1172activity for which Congress intended to grant absolution with the passage of section 230. With respect to the defamatory content, the website operator was merely a passive conduit and thus could not be held liable for failing to detect and remove it.32
By contrast, Roommate both elicits the allegedly illegal content and makes aggressive use of it in conducting its business. Roommate does not merely provide a framework that could be utilized for proper or improper purposes; rather, Roommate’s work in developing the discriminatory questions, discriminatory answers and discriminatory search mechanism is directly related to the alleged illegality of the site. Unlike Carafano, where the website operator had nothing to do with the user’s decision to enter a celebrity’s name and personal information in an otherwise licit dating service, here, Roommate is directly involved with developing and enforcing a system that subjects subscribers to allegedly discriminatory housing practices.
Our ruling today also dovetails with another facet of Carafano: The mere fact that an interactive computer service “classifies user characteristics ... does not transform [it] into a ‘developer’ of the ‘underlying misinformation.’ ” Carafano, 339 F.3d at 1124. Carafano, like Batzel, correctly anticipated our common-sense interpretation of the term “developH” in section 230. Of course, any classification of information, like the sorting of dating profiles by the type of relationship sought in Carafano, could be construed as “develop[ment]” under an unduly broad reading of the term. But, once again, such a broad reading would sap section 230 of all meaning.
The salient fact in Carafano was that the website’s classifications of user characteristics did absolutely nothing to enhance the defamatory sting of the message, to encourage defamation or to make defamation easier: The site provided neutral tools specifically designed to match romantic partners depending on their voluntary inputs. By sharp contrast, Roommate’s website is designed to force subscribers to divulge protected characteristics and discriminatory preferences, and to match those who have rooms with those who are looking for rooms based on criteria that appear to be prohibited by the FHA.33
*11733. Councils finally argue that Roommate should be held liable for the discriminatory statements displayed in the “Additional Comments” section of profile pages. At the end of the registration process, on a separate page from the other registration steps, Roommate prompts subscribers to “tak[e] a moment to personalize your profile by writing a paragraph or two describing yourself and what you are looking for in a roommate.” The subscriber is presented with a blank text box, in which he can type as much or as little about himself as he wishes. Such essays are visible only to paying subscribers.
Subscribers provide a variety of provocative, and often very revealing, answers. The contents range from subscribers who “[p]ref[er] white Male roommates” or require that “[t]he person applying for the room MUST be a BLACK GAY MALE” to those who are “NOT looking for black muslims.” Some common themes are a desire to live without “drugs, kids or animals” or “smokers, kids or druggies,” while a few subscribers express more particular preferences, such as preferring to live in a home free of “psychos or anyone on mental medication.” Some subscribers are just looking for someone who will get along with their significant other34 or with their most significant Other.35
Roommate publishes these comments as written.36 It does not provide any specific guidance as to what the essay should contain, nor does it urge subscribers to input *1174discriminatory preferences. Roommate is not responsible, in whole or in part, for the development of this content, which comes entirely from subscribers and is passively displayed by Roommate. Without reviewing every essay, Roommate would have no way to distinguish unlawful discriminatory preferences from perfectly legitimate statements. Nor can there be any doubt that this information was tendered to Roommate for publication online. See pp. 1170-71 & n.29 supra. This is precisely the kind of situation for which section 230 was designed to provide immunity. See pp. 1162-64 supra.
The fact that Roommate encourages subscribers to provide something in response to the prompt is not enough to make it a “develop[er]” of the information under the common-sense interpretation of the term we adopt today. It is entirely consistent with Roommate’s business model to have subscribers disclose as much about themselves and their preferences as they are willing to provide. But Roommate does not tell subscribers what kind of information they should or must include as “Additional Comments,” and certainly does not encourage or enhance any discriminatory content created by users. Its simple, generic prompt does not make it a developer of the information posted.37
Councils argue that — given the context of the discriminatory questions presented earlier in the registration process — the “Additional Comments” prompt impliedly suggests that subscribers should make statements expressing a desire to discriminate on the basis of protected classifications; in other words, Councils allege that, by encouraging some discriminatory preferences, Roommate encourages other discriminatory preferences when it gives subscribers a chance to describe themselves. But the encouragement that bleeds over from one part of the registration process to another is extremely weak, if it exists at all. Such weak encouragement cannot strip a website of its section 230 immunity, lest that immunity be rendered meaningless as a practical matter.38
We must keep firmly in mind that this is an immunity statute we are expounding, a provision enacted to protect websites against the evil of liability for failure to remove offensive content. See pp. 1162-64 supra. Websites are complicated enterprises, and there will always be close cases where a clever lawyer could argue that something the website operator did encouraged the illegality. Such close cases, we believe, must be resolved in favor of immunity, lest we cut the heart out of section 230 by forcing websites to face death by ten thousand duck-bites, fighting off claims that they promoted or encouraged — or at least tacitly assented to — the illegality of third parties. Where it is very clear that the website directly participates in developing the alleged illegality — as it is clear here with respect to Roommate’s questions, answers and the resulting profile pages — immunity will be lost. But in cases of enhancement by implication or *1175development by inference — such as with respect to the “Additional Comments” here — section 230 must be interpreted to protect websites not merely from ultimate liability, but from having to fight costly and protracted legal battles.
The dissent prophesies doom and gloom for countless Internet services, Dissent at 1183-84, but fails to recognize that we hold part of Roommate’s service entirely immune from liability. The search engines the dissent worries about, id., closely resemble the “Additional Comments” section of Roommate’s website. Both involve a generic text prompt with no direct encouragement to perform illegal searches or to publish illegal content. We hold Roommate immune and there is no reason to believe that future courts will have any difficulty applying this principle.39 The message to website operators is clear: If you don’t encourage illegal content, or design your website to require users to input illegal content, you will be immune.
We believe that this distinction is consistent with the intent of Congress to preserve the free-flowing nature of Internet speech and commerce without unduly prejudicing the enforcement of other important state and federal laws. When Congress passed section 230 it didn’t intend to prevent the enforcement of all laws online; rather, it sought to encourage interactive computer services that provide users neutral tools to post content online to police that content without fear that through their “good Samaritan ... screening of offensive material,” 47 U.S.C. § 230(c), they would become liable for every single message posted by third parties on their website.
* * *
In light of our determination that the CDA does not provide immunity to Roommate for all of the content of its website and email newsletters, we remand for the district court to determine in the first instance whether the alleged actions for which Roommate is not immune violate the Fair Housing Act, 42 U.S.C. § 3604(c).40 We vacate the dismissal of the state law claims so that the district court may reconsider whether to exercise its supplemental jurisdiction in light of our ruling on the federal claims. Fredenburg v. Contra Costa County Dep’t of Health Servs., 172 F.3d 1176, 1183 (9th Cir.1999). We deny Room*1176mate’s cross-appeal of the denial of attorneys’ fees and costs; Councils prevail on some of their arguments before us so their case is perforce not frivolous.
REVERSED in part, VACATED in part, AFFIRMED in part and REMANDED. NO COSTS.
. This appeal is taken from the district court’s order granting defendant’s motion for summary judgment, so we view contested facts in the light most favorable to plaintiffs. See Winterrowd v. Nelson, 480 F.3d 1181, 1183 n. 3 (9th Cir.2007).
. For unknown reasons, the company goes by the singular name “Roommate.com, LLC” but pluralizes its website’s URL, www. roommates. com.
.In the online context, "posting” refers to providing material that can be viewed by other users, much as one “posts” notices on a physical bulletin board.
. The Fair Housing Act prohibits certain forms of discrimination on the basis of "race, color, religion, sex, familial status, or national origin.” 42 U.S.C. § 3604(c). The California fair housing law prohibits discrimination on the basis of "sexual orientation, marital status, ... ancestry, ... source of income, or disability,” in addition to reiterating the federally protected classifications. Cal. Gov. Code § 12955.
. The Supreme Court held some portions of the CDA to be unconstitutional. See Reno v. ACLU, 521 U.S. 844, 117 S.Ct. 2329, 138 L.Ed.2d 874 (1997). The portions relevant to this case are still in force.
. Section 230 defines an "interactive computer service” as "any information service, systern, or access software provider that provides or enables computer access by multiple users to a computer server.” 47 U.S.C. § 230(f)(2); see Carafano v. Metrosplash.com, Inc., 207 F.Supp.2d 1055, 1065-66 (C.D.Cal. 2002) (an online dating website is an "interactive computer service" under the CDA), aff'd, 339 F.3d 1119 (9th Cir.2003). Today, the most common interactive computer services are websites. Councils do not dispute that Roommate’s website is an interactive computer service.
.The Act also gives immunity to users of third-party content. This case does not involve any claims against users so we omit all references to user immunity when quoting and analyzing the statutory text.
. See, e.g., Anthony v. Yahoo! Inc., 421 F.Supp.2d 1257, 1262-63 (N.D.Cal.2006) (Yahoo! is not immune under the CDA for allegedly creating fake profiles on its own dating website).
. Prodigy was an online service provider with 2 million users, which seemed like a lot at the time.
. A "message board” is a system of online discussion allowing users to "post” messages. Messages are organized by topic — such as the "finance” message board at issue in Stratton Oakmont — and the system generally allows users to read and reply to messages posted by others.
. CompuServe was a competing online service provider of the day.
. While the Conference Report refers to this as "[o]ne of the specific purposes” of section 230, it seems to be the principal or perhaps the only purpose. The report doesn't describe *1164any other purposes, beyond supporting “the important federal policy of empowering parents to determine the content of communications their children receive through interactive computer services.” H.R.Rep. No. 104-458, at 194 (1996) (Conf.Rep.), as reprinted in 1996 U.S.C.C.A.N. 10, 207-08.
. The Fair Housing Act prohibits any “statement ... with respect to the sale or rental of a dwelling that indicates ... an intention to make [a] preference, limitation, or discrimination” on the basis of a protected category. 42 U.S.C. § 3604(c) (emphasis added). California law prohibits "any written or oral inquiry concerning the” protected status of a housing seeker. Cal. Gov.Code § 12955(b).
. The Seventh Circuit has expressly held that inquiring into the race and family status of housing applicants is unlawful. See, e.g., Jancik v. HUD, 44 F.3d 553, 557 (7th Cir.1995).
.The dissent stresses the importance of the Internet to modem life and commerce, Dissent at 1176, and we, of course, agree: The Internet is no longer a fragile new means of communication that could easily be smothered in the cradle by overzealous enforcement of laws and regulations applicable to briclc- and-morlar businesses. Rather, it has become a dominant — perhaps the preeminent— means through which commerce is conducted. And its vast reach into the lives of millions is exactly why we must be careful not to exceed the scope of the immunity provided by Congress and thus give online businesses an unfair advantage over their real-world coun*1165terparts, which must comply with laws of general applicability.
.Roommate argues that Councils waived the argument that the questionnaire violated the FHA by failing to properly raise it in the district court. But, under our liberal pleading standard, it was sufficient for Councils in their First Amended Complaint to allege that Roommate “encourages” subscribers to state discriminatory preferences. See Johnson v. Barker, 799 F.2d 1396, 1401 (9th Cir. 1986).
. A drop-down menu allows a subscriber to select answers only from among options provided by the website.
. See also discussion of Batzel pp. 1170-71 infra.
. The dissent may be laboring under a misapprehension as to how the Roommate website is alleged to operate. For example, the dissent spends some time explaining that certain portions of the user profile application are voluntary. Dissent at 1180-82. We do not discuss these because plaintiffs do not base their claims on the voluntary portions of the application, except the “Additional Comments” portion, discussed below, see pp. 1173-75 infra. The dissent also soft-pedals Roommate’s influence on the mandatory portions of the applications by referring to it with such words as "encourage” or “encouragement” or "solicitation.” Dissent at 1185; see id. at 1188. Roommate, of course, does much more than encourage or solicit; it forces users to answer certain questions and thereby provide information that other clients can use to discriminate unlawfully.
. When a prospective subscriber submits his application, Roommate’s server presumably checks it to ensure that all required fields are complete, and drat any credit card information is not fraudulent or erroneous. Moreover, some algorithm developed by Roommate then decodes the input, transforms it into a profile page and notifies other subscribers of a new applicant or individual offering housing matching their preferences.
. Other circuits have held that it is unlawful for housing intermediaries to "screen” prospective housing applicants on the basis of race, even if the preferences arise with landlords. See Jeanty v. McKey & Poague, Inc., 496 F.2d 1119, 1120-21 (7th Cir.1974).
. Development, it will be recalled, has many meanings, which differ materially depending on context. Thus, "development” when used as part of the phrase "research and development” means something quite different than when referring to "mental development,” and something else again when referring to "real estate development,” "musical development” or "economic development.”
. It is perfectly legal to discriminate along those lines in dating, and thus there can be no claim based solely on the content of these questions.
. Requiring website owners to refrain from taking affirmative acts that are unlawful does not strike us as an undue burden. These are, after all, businesses that are being held responsible only for their own conduct; there is no vicarious liability for the misconduct of their customers. Compliance with laws of general applicability seems like an entirely justified burden for all businesses, whether they operate online or through quaint brick- and-mortar facilities. Insofar, however, as a plaintiff would bring a claim under state or federal law based on a website operator’s passive acquiescence in the misconduct of its users, the website operator would likely be entitled to CDA immunity. This is true even if the users committed their misconduct using electronic tools of general applicability provided by the website operator.
.Of course, the logic of Roommate’s argument is not limited to discrimination based on these particular criteria. If Roommate were free to discriminate in providing housing services based on sex, there is no reason another website could not discriminate based on race, religion or national origin. Nor is its logic limited to housing; it would apply equally to websites providing employment or educational opportunities — or anything else, for that matter.
. The dissent argues that Roommate is not liable because the decision to discriminate on these grounds does not originate with Roommate; instead, “users have chosen to select characteristics that they find desirable.” Dissent at 1185. But, it is Roommate that forces users to express a preference and Roommate that forces users to disclose the information that can form the basis of discrimination by others. Thus, Roommate makes discrimination both possible and respectable.
. Apparently, it was common practice for this editor to receive and forward tips from his subscribers. In effect, the newsletter served as a heavily moderated discussion list.
. As an initial matter, the Batzel panel held that the defendant newsletter editor was a "user” of an interactive computer service within the definition provided by section 230. While we have our doubts, we express no view on this issue because it is not presented to us. See p. 1162 n. 7 supra. Thus, we assume that the editor fell within the scope of section 230’s coverage without endorsing Batzel' s analysis on this point.
. As Batzel pointed out, there can be no meaningful difference between an editor starting with a default rule of publishing all submissions and then manually selecting material to be removed from publication, and a *1171default rule of publishing no submissions and manually selecting material to be published— they are flip sides of precisely the same coin. Batzel, 333 F.3d at 1032 ("The scope of [section 230] immunity cannot turn on whether the publisher approaches the selection process as one of inclusion or removal, as the difference is one of method or degree, not substance.”).
. The dissent scores a debater’s point by noting that the same activity might amount to "development” or not, depending on whether it contributes materially to the illegality of the content. Dissent at 1182-83. But we are not defining "development” for all purposes; we are defining the term only for purposes of determining whether the defendant is entitled to immunity for a particular act. This definition does not depend on finding substantive liability, but merely requires analyzing the context in which a claim is brought. A finding that a defendant is not immune is quite distinct from finding liability: On remand, Roommate may still assert other defenses to liability under the Fair Housing Act, or argue that its actions do not violate the Fair Housing Act at all. Our holding is limited to a determination that the CDA provides no immunity to Roommate's actions in soliciting and developing the content of its website; whether that content is in fact illegal is a question we leave to the district court.
. We disavow any suggestion that Carafano holds an information content provider automatically immune so long as the content originated with another information content provider. 339 F.3d at 1125.
. Section 230 requires us to scrutinize particularly closely any claim that can be boiled down to the failure of an interactive computer service to edit or block user-generated content that it believes was tendered for posting online, see pp. 1170-71 supra, as that is the veiy activity Congress sought to immunize by passing the section. See pp. 1162-64 supra.
. The dissent coyly suggests that our opinion "sets us apart from" other circuits, Dissent at 1177, 1179-80, carefully avoiding the phrase “intercircuit conflict.” And with good reason: No other circuit has considered a case like ours and none has a case that even arguably conflicts with our holding today. No case cited by the dissent involves active participation by the defendant in the creation or development of the allegedly unlawful content; in each, the interactive computer service provider passively relayed content generated by third parties, just as in Stratton Oakmont, and did not design its system around the dissemination of unlawful content.
In Chicago Lawyers' Committee for Civil Rights Under Law, Inc. v. craigslist, Inc., 519 F.3d 666 (7th Cir.2008), the Seventh Circuit held the online classified website craigslist immune from liability for discriminatory housing advertisements submitted by users. Craigslist's service works very much like the "Additional Comments” section of Roommate’s website, in that users are given an open text prompt in which to enter any description of the rental property without any structure imposed on their content or any requirement to enter discriminatory information: "Nothing in the service craigslist offers induces anyone to post any particular listing or express a preference for discrimination....” 519 F.3d at 671-72. We similarly hold the "Additional Comments” section of Roommate's site immune, see pp. 1173-75 infra. Consistent with our opinion, the Sev*1173enth Circuit explained the limited scope of section 230(c) immunity. Craigslist, at 671-72. More directly, the Seventh Circuit noted in dicta that "causing a particular statement to be made, or perhaps [causing] the discriminatory content of a statement ” might be sufficient to create liability for a website. At 671-72 (emphasis added). Despite the dissent's attempt to imply the contrary, the Seventh Circuit’s opinion is actually in line with our own.
In Universal Communication Systems v. Lycos, Inc., the First Circuit held a message board owner immune under the CDA for defamatory comments posted on a message board. 478 F.3d 413 (1st Cir.2007). The allegedly defamatory comments were made without any prompting or encouragement by defendant: ”[T]here is not even a colorable argument that any misinformation was prompted by Lycos’s registration process or its link structure.” Id. at 420.
Green v. America Online, 318 F.3d 465 (3d Cir.2003), falls yet farther from the mark. There, AOL was held immune for derogatory comments and malicious software transmitted by other defendants through AOL’s "Romance over 30” "chat room.” There was no allegation that AOL solicited the content, encouraged users to post harmful content or otherwise had any involvement whatsoever with the harmful content, other than through providing "chat rooms” for general use.
In Ben Ezra, Weinstein, and Co. v. America Online Inc., 206 F.3d 980 (10th Cir.2000), the Tenth Circuit held AOL immune for relaying inaccurate stock price information it received from other vendors. While AOL undoubtedly participated in the decision to make stock quotations available to members, it did not cause the errors in the stock data, nor did it encourage or solicit others to provide inaccurate data. AOL was immune because "Plaintiff could not identify any evidence indicating Defendant [AOL] developed or created the stock quotation information.” Id. at 985 n. 5. And, finally, in Zeran v. America Online, Inc., 129 F.3d 327 (4th Cir.1997), the Fourth Circuit held AOL immune for yet another set of defamatory and harassing message board postings. Again, AOL did not solicit the harassing content, did not encourage others to post it, and had nothing to do with its creation other than through AOL’s role as the provider of a generic message board for general discussions.
. "The female we are looking for hopefully wont [sic] mind having a little sexual incounter [sic] with my boyfriend and I [very sic].”
. "We are 3 Christian females who Love our Lord Jesus Christ.... We have weekly bible studies and bi-weekly times of fellowship.”
. It is unclear whether Roommate performs any filtering for obscenity or "spam,” but even if it were to perform this kind of minor editing and selection, the outcome would not change. See Batzel, 333 F.3d at 1031.
. Nor would Roommate be the developer of discriminatory content if it provided a free-text search that enabled users to find keywords in the "Additional Comments” of others, even if users utilized it to search for discriminatory keywords. Providing neutral tools for navigating websites is fully protected by CDA immunity, absent substantial affirmative conduct on the part of the website creator promoting the use of such tools for unlawful purposes.
. It’s true that, under a pedantic interpretation of the term “develop,” any action by the website — including the mere act of making a text box available to write in — could be seen as “develop [ing]” content. However, we have already rejected such a broad reading of the term "develop” because it would defeat the purpose of section 230. See pp. 1167-69 supra.
. The dissent also accuses us of creating uncertainty that will chill the continued growth of commerce on the Internet. Dissent at 1187. Even looking beyond the fact that the Internet has outgrown its swaddling clothes and no longer needs to be so gently coddled, see p. 1164-65 n. 15 supra, some degree of uncertainty is inevitable at the edge of any rule of law. Any immunity provision, including section 230, has its limits and there will always be close cases. Our opinion extensively clarifies where that edge lies, and gives far more guidance than our previous cases. While the dissent disagrees about the scope of the immunity, there can be little doubt that website operators today know more about how to conform their conduct to the law than they did yesterday.
However, a larger point remains about the scope of immunity provisions. It's no surprise that defendants want to extend immunity as broadly as possible. We have long dealt with immunity in different, and arguably far more important, contexts — such as qualified immunity for police officers in the line of duty, see Clement v. City of Glendale, 518 F.3d 1090 (9th Cir.2008) — and observed many defendants argue that the risk of getting a close case wrong is a justification for broader immunity. Accepting such an argument would inevitably lead to an endless broadening of immunity, as every new holding creates its own borderline cases.
. We do not address Roommate's claim that its activities are protected by the First Amendment. The district court based its decision entirely on the CDA and we refrain from deciding an issue that the district court has not had the opportunity to evaluate. See Mukherjee v. INS, 793 F.2d 1006, 1010 (9th Cir. 1986).