What with Jeff's blog post today, possibly this is a good time to ask: who actually owns the copyright to questions, answers and comments submitted to StackOverflow and relatives?

Over in this question about licensing, we have the OP reaching the conclusion that SO owns the copyright and is licensing it under CC-Attribution-Sharealike, with no apparent confirmation or denial from staff, and in an answer in another thread we have a moderator asserting that Jeff owns the copyright to SO content.

As I note in a comment on the latter, though (which was met with deafening silence), I'm failing to find any evidence that this is the case. I've looked for any kind of terms of service I may have agreed to indicating that I am signing over ownership of my words when I hit submit, and I can't find one. Certainly the fact that I'm agreeing to CC-Attribution-Sharealike licensing is clear enough, but it seems to me as if I am retaining copyright while agreeing to those licensing terms, and S[OFU] is using what I have written under that license.

What's the deal? Did I forget about something that I agreed to in the signup process (and if so, why can't I find it afterward)? Do the owners and administrators of S[OFU] believe that they own copyright to the UGC? Just what is going on here?

Edit as to why this matters (from answer comment thread): If I retain copyright, I can also choose to license the original content to other parties under other terms (such as using a zero-requirements license, using an attribution-required license without sharealike, etc). If SO has the copyright, I can't.

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    This is a good question, and I think that stackoverflow.com LLC should release some clarifications/discussion on the license ramifications. – Paul Nathan Aug 12 '09 at 19:27
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    Agreed. I know I've shied away from answering certain questions because of the vague licensing...and I have no problem with not participating at all, if I've been secretly signing away the rights to my answers. – Andy Mikula Aug 12 '09 at 19:47
  • what have we ever done to indicate that you would be "signing away the rights to your answer"? Compare us with any other site on the internet in this regard. – Jeff Atwood Aug 16 '09 at 8:05
  • @Jeff Atwood: See my comment to your answer (posted there so it'll show up in your responses). – chaos Aug 16 '09 at 14:19
  • The question is a good one, since chaos was apparently given false information. IANAL, but I believe it's hard to implicitly lose copyright, unless you're in a work-for-hire situation. – David Thornley Aug 18 '09 at 17:30
up vote 10 down vote accepted

The footer says:

Honestly, you should consult a lawyer if you really, really need this answered in some highly legal definitive way. I suggest starting with the Creative Commons website?

How does a Creative Commons license operate?

A Creative Commons license is based on copyright. So they apply to all works that are protected by copyright law. The kinds of works that are protected by copyright law are books, websites, blogs, photographs, films, videos, songs and other audio & visual recordings, for example. Software programs are also protected by copyright but, as explained below, we do not recommend that you apply a Creative Commons license to software code.

Creative Commons licenses give you the ability to dictate how others may exercise your copyright rights—such as the right of others to copy your work, make derivative works or adaptations of your work, to distribute your work and/or make money from your work. They do not give you the ability to restrict anything that is otherwise permitted by exceptions or limitations to copyright—including, importantly, fair use or fair dealing—nor do they give you the ability to control anything that is not protected by copyright law, such as facts and ideas.

Creative Commons licenses attach to the work and authorize everyone who comes in contact with the work to use it consistent with the license. This means that if Bob has a copy of your Creative Commons-licensed work, Bob can give a copy to Carol and Carol will be authorized to use the work consistent with the Creative Commons license. You then have a license agreement separately with both Bob and Carol.

You should be aware that Creative Commons licenses only affect your rights under copyright. You are not licensing your trademark or patent rights, if any, when you apply a CC license to your work.

Creative Commons licenses are expressed in three different formats: the Commons Deed (human-readable code), the Legal Code (lawyer-readable code); and the metadata (machine readable code). You don’t need to sign anything to get a Creative Commons license—just select your license at our ‘Choose License’ page.

One final thing you should understand about Creative Commons licenses is that they are all non-exclusive. This means that you can permit the general public to use your work under a Creative Commons license and then enter into a separate and different non-exclusive license with someone else, for example, in exchange for money.

IANAL, but my interpretation of that is anything you post here, you are implicitly posting and licensing to Stack Exchange, Inc. under cc-by-sa 3.0. Which should be OK unless you're one of those people who wears a tinfoil hat, since it's an extremely permissive "everyone wins" license.

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    Re what have you guys ever done to indicate you're taking over copyright: not contradicting Evert or Joel Coehoorn when they asserted SO's/your ownership of copyright in the question and answer I linked to, basically. Don't get me wrong, it's awesome that you're doing things better than every other site on the internet. But everyone else doing it the other way is probably why people (including some acting in a semi-official capacity) easily reach the wrong conclusion. So if this is a key differentiator for you guys, maybe it would be wise to be at slightly greater pains to make it clear. – chaos Aug 16 '09 at 14:18
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    @chaos, no. What Jeff is doing is requiring every post here to fall under the cc-wiki license. Neither Jeff or anyone else at SO owns the copyright over our posts, and they should not even want this! (It would make them responsible for every bad piece of advise that's given here!) You still own copyright over your own posts here. And you've given SO and everyone else in this world the right to use your post any way they like, as long as they mention you as author and use the same cc-wiki license for the the derived work. – Wim ten Brink Aug 16 '09 at 20:54
  • @Workshop Alex: Um, right. I don't see how your comment responds to mine. I was trying to find out whether staff were asserting site ownership of copyright, as moderator Joe Coehoorn did. – chaos Aug 17 '09 at 9:57
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    So, Jeff, I'd really like to read your answer as answering my question, but when I really look at it, it doesn't. My question is really nothing to do with the properties of cc-wiki, because I'm not asking about the licensing, I'm asking about ownership. Licensing copyrighted material and transferring copyright are, of course, completely different activities. My question, short version, is: do SO staff believe that users are transferring copyright to SO LLC when they post content? Your comment on the question strongly implies that the answer is "no" but doesn't say so. – chaos Aug 17 '09 at 22:52
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    Please, then, if the answer is in fact no, would you be so kind as to say something like "you are not transferring copyright of your posts to SO, you are licensing them"? And again, the reason I'm asking this isn't that I have a big tinfoil hat on, it's that users and moderators are reaching the conclusion that SO is assuming copyright to UGC and no one is contradicting them. – chaos Aug 17 '09 at 22:53
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    let's go up a bit. Who here works for stackoverflow.com llc? Only people that formally work for stackoverflow.com llc can make binding statements about what the company does or doesn't do. – Jeff Atwood Aug 17 '09 at 23:31
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    Sure, Evert and Joe Coehoorn's statements have no legal force. What they do is point out an ambiguity in the IP situation. Which is why I'm asking someone I'm pretty sure works for stackoverflow.com, yourself, for clarification. Which is bizarrely non-forthcoming. FWIW, I would be perfectly thrilled with a non-binding statement of intent clarifying whether stackoverflow.com means to be assuming copyright of UGC. I just want to know what you guys consider to be going on. – chaos Aug 18 '09 at 2:00
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    Uhm. I'm really sorry that this is, for some reason, so difficult, but having come this far, I kinda feel like I should try to get an answer to the question I'm asking. And no, that doesn't answer it. As noted in other comments, "user contributed content, to which users retain copyright, licensed under cc-wiki with attribution required" and "user contributed content, to which SO holds copyright, licensed under cc-wiki with attribution required" are both expansions of the footer language that don't contradict it. It's ambiguous. It is this exact ambiguity I'm asking to have clarified. – chaos Aug 18 '09 at 4:54
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    your question is so nonsensical I still don't understand it. How can we POSSIBLY OWN COPYRIGHT TO SOMETHING YOU WROTE? We license it. Under cc-wiki. I'm sorry, this is so utterly obvious to me, and explained by the cc-wiki answer above, that I honestly still don't understand what the problem is. – Jeff Atwood Aug 18 '09 at 10:54
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    I don't know, dude, ask Evert and Joe Coehoorn. Apparently it's such common internet practice that you're giving up your IP when you hit submit that people assume that's what's happening with SO. Anyway, I'll take "We license it" as near enough to a straight answer. The reason that referring to cc-wiki repeatedly doesn't clarify anything is that cc-wiki could be the terms under which SO is licensing content it owns as easily as the terms under which UGC is licensed to SO. – chaos Aug 18 '09 at 15:07
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    I have had the same question as @chaos, and no, the language doesn't make it clear. Here's the crux: there are two licensing stages happening. The first, when contributors write something, and the second, when SO publishes it and random users copy it. The footer on the SO site is ambiguous, because it could apply to either licensing, or else just one or the other. And I know I didn't sign any contributor agreement that I was licensing (but not transferring) my contribution to SO. I actually do agree to something like that on virtually every other site on the internet. – Bill Karwin Aug 22 '09 at 6:25
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    One more point: I have written plenty of code and documentation that I don't own the copyright to. Anything I've written for an employer, for starters. – Bill Karwin Aug 22 '09 at 6:41
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    We do need to debate the meaning of "is" because you don't get it. Saying that user submitted content is licensed under cc-wiki is an assertion, not a request for consent or a requirement upon authors. You can't make that assertion without first asking for permission from the copyright holders. What could possibly be so painful about turning the implicit demand for licensing to StackOverflow into an explicit one? It makes no sense. StackOverflow holds so much user content that it's simply ridiculous to have no legal policy or, apparently, understanding of copyright law. – Instance Hunter Mar 2 '10 at 16:08
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    FWIW, wikipedia has a link to its terms of use (wikimediafoundation.org/wiki/Terms_of_Use) on every page, which state, among other things, "for any text you hold the copyright to, by submitting it, you agree to license it under the Creative Commons Attribution/Share-Alike License 3.0". That's pretty clear, maybe you should do that too. – itsadok Apr 20 '10 at 7:05
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    @JeffAtwood: "How can we POSSIBLY OWN COPYRIGHT TO SOMETHING YOU WROTE?" By putting a clause in the terms of service that says we assign copyright to you for anything we submit, which is the norm for most sites. (The fact that you then license it under CC is not the point.) The copyright holder can dual-license their content; someone using it under CC license cannot. Wikipedia's switch from GFDL to CC required a dirty hack to the GFDL because their content has thousands of copyright holders who would all need to approve the change otherwise. – endolith Jan 5 '13 at 6:34

From the footer:

"site design and logo is © 2009 stackoverflow.com LLC; user contributed content licensed under cc-wiki with attribution required"

In other words, you own the copyright on the content you have generated, however, you have also granted a licence for it to be used under those terms.

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    That's one interpretation, yeah, and it happens to be mine. But it's not exactly inescapable; "user contributed content, to which users retain copyright, licensed under cc-wiki with attribution required" and "user contributed content, to which SO holds copyright, licensed under cc-wiki with attribution required" are both expansions of the original that don't contradict it. That's why I'd like some official clarification. – chaos Aug 12 '09 at 15:47
  • Yep, it's similar to GPL in that regard. The person who holds the copyright is somewhat irrelevant once the content has been licensed and rekeased under these terms. AFAIK, they can't change their minds, strictly speaking. – ベレアー アダム Aug 12 '09 at 15:48
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    Revocability is a little more up in the air than that, much to everyone's dismay, but it's not really irrelevant even if irrevocable. If I retain copyright, I can also choose to license the original content to other parties under other terms (such as releasing it into the public domain, using an attribution-required license without sharealike, etc). If SO has the copyright, I can't. – chaos Aug 12 '09 at 15:51
  • Excellent point, I hadn't considered additional licensing. Maybe you can add text to that effect in your OP? – ベレアー アダム Aug 12 '09 at 15:52
  • Yeah, good idea. – chaos Aug 12 '09 at 15:56
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    It occurs to me that if you come along as an anonymous user, and ask a question, there is no acceptance of any terms of service, so maybe it's even more ambiguous than I first thought. My interpretation, as a lay person (I.e. I'm not qualified to give legal advice) would be that you cannot enter into an [exclusive] contract with your contributions, so you'd retain copyright. I'd also assume that S* should explicitly ask your permission or at least gain your acknowledged that it can be licenced as it is – Rowland Shaw Aug 12 '09 at 18:05
  • If Rowland Shaw is right, then I think Jeff needs to make deleted questions and answers removed from the database forever, as deleting is me revoking my license to SO to use my content. And the data dumps? Well...wow...this could be problematic. – Thomas Owens Aug 12 '09 at 18:12
  • ...and reading the CC licence, it is "worldwide, royalty-free, non-exclusive, perpetual", I.e. I believe we could release our contributions (that don't include others' work) elsewhere under other licences if we so choose. – Rowland Shaw Aug 12 '09 at 18:13
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    @Thomas Owens, you can't revoke the license, except automatically if the licensee are in breach of the license. See my answer. :) – KTC Aug 12 '09 at 19:00
  • And what if I Googled every bit of my "copyrighted" answer? – Ivo Flipse Aug 12 '09 at 19:57
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    @Thomas Owens, @KTC: Right, which means that any actions taken by SO when you hit "delete" are a courtesy, not a legal responsibility. – chaos Aug 12 '09 at 22:55

Oh, what the hulk, let's make a shorter answer. SO owns the copyright over the domain, the graphics, the software of this site (if SO created it themselves) and basically any message that they posted themselves. They also require every member who posts here to license their post using the cc-wiki license. This means you're still the owner of your own posts. It's just that SO can use your post if they ever print all answers inside a book and all they have to do is write somewhere in that book that you're the author of certain parts. And no, you won't get a dime for your contribution.

Then again, once they print that book, it gets infected by the cc-wiki license itself, thus anyone could copy this book for free. That's because of the 'Share Alike' restriction. This would basically be a big showstopper to some commercial use of any content here, although it's still possible.

You wrote your question so you own the copyright over it. You could write the same question somewhere else with a different license without any problems. You are the owner. It's just that you also gave me the right to publish your question in my book, as long as I mention that I got this question from you. (And thereby, my book is infected with CC-BY-SA.)

  • Glad to read this. Very clear. – jjnguy Aug 18 '09 at 17:31

Without question, the contributor retains copyright to their contribution. By their action of posting the content, they have agreed to license it under (in this case) CC-BY-SA 2.5. The terms of which is

grants You a worldwide, royalty-free, non-exclusive, perpetual (for the duration of the applicable copyright) license

That mean you can release it under other license if you want. The license is set out in such way to also mean you can't revoke the license you've granted to SO (and other people) to use the content, except under the explicitly specified terms, where there is only one way. If SO (or whoever) are in breach of the license, then the rights granted to that party, and that party alone, is automatically terminated. No termination occurs to any other party, whether using the original or derivative content.


  • I believe there might be issue with the point of acceptance of the licence, as it does not state anywhere that that is the case, nor are there any formal terms of service available – Rowland Shaw Aug 12 '09 at 20:51
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    it states on every page in the footer. Are you really asking for a click-through licensing dialog on every post? – Jeff Atwood Aug 16 '09 at 7:46
  • I tend to have a tin foil hat to hand when it comes to hosting sites with UGC ;) – Rowland Shaw Aug 16 '09 at 8:01

(For Dutch/European people mostly) A lawyer could provide more precise details but in general, when you write something original and with a personal mark (signature) then your comments would be protected by copyright. However, many responses here are just facts to help someone to solve a problem and facts cannot be copyrighted! However, comments could break certain laws, especially when you start to put a hyper link in your replies. Most links would still be okay, though. But a link to a racist site could be illegal in Europe. Or a link to illegal software. Or a trademark violation when the link claims to point to HP, yet the URL points to Dell... The author is the one responsible for these remarks, the site owners just have to remove those "illegal" remarks or become partially responsible themselves.

If comments would be owned by the site moderators, they could end up in a lot of legal problems. Basically, in that case a visitor could post a link to illegal software and the site owners would have to face legal consequences. They would not be protected by the safe harbour principle, since they own the comments! So smart forum-owners will never ever want to own copyrights to any comments.

Another interesting part is that posts here fall under the cc-wiki license. Basically, that's the main rule here when you start participating. This is a rule that you accepted when you joined this site, and it can be enforced simply because these rules are a visible part of every page here! However, changing those rules would not be allowed in Europe, so if the owners discover an error which they want to fix, they do need to notify the members about this change, allowing members to resign from this site! But what effect would resigning have for your posts? You could revoke the license on your comments but that would only have effect from that moment on.

And what does the cc-wiki actually mean? Well, it means that when someone is copying your comment, they will have to make it clear whom wrote the original text. (Attribution) Also, if your text becomes part of a bigger piece of text, that bigger piece of text would require at least the same CC license. But hey, I could publish a book with all the questions and answers from this site and sell it, without having to share a dime with any other visitor here! The book would just need proper attribution and others would be free to make copies of this book and share it for free in digital form. (Or Xerox the whole book and give it away for free on dead trees.)

And what if you don't agree with this? What if you want to comment, but you don't want your answer to be part of this license? Well, you could always put the answer on your own website and add a link here to your site. However, you cannot copy the question to your site because your site would then fall under the cc-wiki license. Then again, if the question is very simple and didn't need much creativity to write, you can use the question without being infected by cc-wiki. Why? Because the text still needs to be creative. Just asking if anyone knows a good Paint application is not creative. Asking for the risks of upgrading from Windows 2000 to Windows 7 isn't creative either. Telling someone how to install the latest driver for their network card is informative but maybe not creative enough to be licensable... (You're just mentioning facts.) Even the description of a film plot on the back of the DVD you just bought might not fall under any license since it just mentions what's happening in the movie. (Which are facts.) However, showing a 10-seconds preview from the same movie or even from the trailer might require a license, though. Unless you're describing that scene as part of a bigger article, in which case it becomes part of a "quote". You can't even use a screenshot from a movie, if it's just meant as decoration. An Ewok image which I saw somewhere on these sites might already be a violation. Then again, it was used as part of a document, referring to the movie and Ewoks in general, making it perfectly legal again.

Basically, licenses aren't black and white. They're just a whole lots of shades of grey. Some dark, some light. But just remember: if a forum owner claims ownership of every message in his forums, he also becomes legally responsible for all those responses. A smart owner would never even consider that kind of responsibility. (But they might add a restriction to the license that you can use here.)

  • At least in the US, while you can't copyright facts, you can copyright their presentation (assuming there's some originality). Therefore, while a quote from the standard wouldn't be copyrightable by me, any explanatory text could well be. – David Thornley Aug 18 '09 at 17:33

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