And a related question, "Who owns the text of an answer I write on StackExchange?"

Hypothetically, If I take the text of an answer I wrote on StackExchange and include it word for word, verbatim, in an article or book I write, would I be running afoul of copyright law?

On this specific question, does anyone know the terms and conditions of this site in detail? What did I agree to when I clicked yes/join? :P

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    $\begingroup$ This is just to mention that "your" answers can include others' edits. Perhaps this is usually a trivial complication, but not always. $\endgroup$
    – Nick Cox
    Commented Nov 2, 2016 at 16:20
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    $\begingroup$ Also, how is anyone to prove that they are the author?! Matthew looks pretty identifiable, and so am I, but there are many pseudonyms or single names here that look utterly ambiguous, A quick scroll through users with highest reputation suggests that the fraction is of the order of a half. I suppose that being coy about who you are -- perfectly allowed, and a few times I've regretted laying myself open to emails from helpless people -- goes with not wanting to claim posts as your intellectual property in any sense. People give freely, in short. $\endgroup$
    – Nick Cox
    Commented Nov 2, 2016 at 18:37
  • $\begingroup$ An interesting question is whether you can sell your answers. For instance, you put them all into a book, publish and sell it on amazon. Or use an idea to build a product, and sell it. Or use other people's posts to build services and products and sell them. etc. $\endgroup$
    – Aksakal
    Commented Nov 3, 2016 at 13:33
  • $\begingroup$ Good question. The responses provided seem to allow a wide leeway in how you choose to use your content but waffle on the specific question of ownership, specifically wrt anonymous posts. Another grey area is the use and/or quotation of posts external to SE. So, for instance, is an anonymous contributor to SE required to quote for attribution a post made anonymously on another blog when incorporating that external post into an SE response? $\endgroup$
    – user78229
    Commented Nov 4, 2016 at 18:34
  • $\begingroup$ @Aksakal: See A book using some of our content?. $\endgroup$ Commented Nov 12, 2016 at 19:47
  • $\begingroup$ @DJohnson: (1) Bear in mind I'm a statistician, not a lawyer, but on reading the terms of service I came across nothing that I could imagine being construed as agreeing to transfer to SE the copyright of anything I posted. And, where I live at any rate, anonymous & pseudonymous writings are covered by copyright. (2) "Is an anonymous contributor to SE required to quote for attribution a post made anonymously on another blog when incorporating that external post into an SE response?" - Yes. A sufficient reason is that other users will ... $\endgroup$ Commented Nov 12, 2016 at 20:15
  • $\begingroup$ ... typically have no means of confirming an alleged identity of posters on different websites. And as I said to @NIckCox, it's a courtesy to readers - they may be interested in looking up the original context (just as when the writers are different). I really can't think of any arguments against the requirement. (Whether the blog requires attribution, or indeed allows re-use at all, of course depends on the terms according to which material is submitted to it.) $\endgroup$ Commented Nov 12, 2016 at 20:16
  • $\begingroup$ @Scortchi, I don't know how to feel about this $\endgroup$
    – Aksakal
    Commented Nov 13, 2016 at 1:02
  • $\begingroup$ @scortchi Thanks for your response. Based on the range of answers, it sounds like there is a lot of latitude in how one can choose to deal with attribution, i.e., there are no hard and fast rules as to how attribution -- particularly anonymous -- is "enforced," if it's enforced at all. To me, this is a statement about the blurry nature of online publishing and is obviously quite different from how citations and references for attribution are handled in scientific, peer-reviewed outlets. $\endgroup$
    – user78229
    Commented Nov 13, 2016 at 20:01

3 Answers 3


Your content is yours: you own it, and can use it howsoever you wish. You may also license it to other people to use it.

By posting something here, you grant Stack Exchange a license to host and reproduce your content. Of course you do: otherwise they couldn’t legally do so. The license is non-exclusive, meaning that you can also license your content to other people (i.e., post it elsewhere). It’s still your content, and you are still the copyright holder.

To be specific, the licence is CC BY-SA 3.0, as specified in the footer of every page. The full license text is, of course, written in legalese, but it’s fairly straightforward. However, Creative Commons themselves provide a neat human-readable summary, as follows:

(Note, this is addressed to the consumer of the content, so the you here is the person reading and potentially reproducing the text. You yourself are “the licensor” — by posting your content to a Stack Exchange site, you are granting this license.)

You are free to:

  • Share — copy and redistribute the material in any medium or format
  • Adapt — remix, transform, and build upon the material for any purpose, even commercially.

The licensor cannot revoke these freedoms as long as you follow the license terms.

Under the following terms:

  • Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.

  • ShareAlike — If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original.

  • No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.

  • $\begingroup$ As Nick mentioned in the comments on the question, this license is granted from all contributors to a question/answer. You have copyright of your contributions only. So you can't license any of your content that has been edited by other people to a third party under a different license (but you can license the original, un-edited content). $\endgroup$
    – naught101
    Commented Mar 2, 2017 at 1:10

See http://stackexchange.com/legal & https://creativecommons.org/licenses/by-sa/3.0/.

For what it's worth, my understanding of all that is that you're perfectly free to reproduce anything you've written here elsewhere; but you can't stop someone else reproducing it provided they properly attribute it to you.

† I'm not giving legal advice, & don't represent Stack Exchange.

  • $\begingroup$ Thanks. I was curious whether my charitable contribution of writing answers goes in the public domain or is actually going into some company's privately owned portfolio. :P $\endgroup$ Commented Nov 1, 2016 at 23:01
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    $\begingroup$ @Matthew Neither. The Creative Commons license isn't placing it in the public domain (which would allow anyone to use it for essentially any purpose in any manner they like), but it allows people to use it if they follow the license (which is roughly along the lines of recognizing your authorship and requiring people using text that's quoting you to do the same). It's better than placing it in the public domain (because it protects it) but makes it available to others. (The information about user contributions being under creative commons is actually at the bottom of this very page.) $\endgroup$
    – Glen_b
    Commented Nov 2, 2016 at 3:49
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    $\begingroup$ But (having asked about it myself), the thinking at StackExchange seems to be that your own stuff is still yours to use, without expecting you to quote the license -- it's a requirement they place on us when we use other people's stuff. So if you wanted to write a book with some of your own text in it, it seems you wouldn't have to quote the licence -- but that wouldn't extinguish the licence that already exists, so other people could still use the text you wrote here because you granted a licence when you posted it (as part of your agreement with StackExchange). $\endgroup$
    – Glen_b
    Commented Nov 2, 2016 at 3:51
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    $\begingroup$ A while back they said they would change to a similar license that they felt would work better for us (I don't see how the proposal would make any substantive difference to StackExchange, so I believe the claim that it was intended to make things better for us in some way, though I don't recall the details) but there were a number of objections to various aspects of the proposal and that intended change is currently on hold, apparently for an indefinite period. $\endgroup$
    – Glen_b
    Commented Nov 2, 2016 at 4:04
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    $\begingroup$ A license is an exemption to copyright that the copyright owner grants. When you license your work to someone else (e.g. Stack Overflow via CC by-sa), you give them permission to use it under certain circumstances. You are still the copyright owner, so you can give anyone else permission to use it in any other way, including yourself. $\endgroup$ Commented Nov 3, 2016 at 0:59

An important other note, aside more licensing issues, is the issue of self-plagiarism. Copying your own work without citation can be considered a form of plagiarism. Now I mainly hear about this in cases where parts of one published article is reused in another, but it might also play a role here. So if you want to be on the safe side: make sure to cite the page you wrote it first, especially if you copy verbatim.

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    $\begingroup$ Self-plagiarism is, in my view, a misnomer. There are plenty of contexts where repeating material is not considered acceptable, and other contexts where it is fine. As a teacher I don't expect anything difficult to be obvious on one explanation. As a researcher I am disconcerted if I come across the same paper in different journals. But as a researcher too I find it difficult to write another paper on a topic without some repetition. These are difficult areas, but the term "self-plagiarism" doesn't help, because there is no question of stealing your own property. $\endgroup$
    – Nick Cox
    Commented Nov 9, 2016 at 18:50
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    $\begingroup$ To the point here, anything I have written on CV is to me fair game for inclusion in a paper. Does anyone think a reference to CV is compulsory? $\endgroup$
    – Nick Cox
    Commented Nov 9, 2016 at 18:52
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    $\begingroup$ @NickCox: I was reading a book only last night in which the author, in a footnote, pointed out sections that were extracted almost verbatim from his previous writings & where to find them. I think that's simply a courtesy to readers, & usual practice. Of course there's not the need for the same care in distinguishing quoted material from new material when the words are all your own. (My understanding, though, is that in this case a reference to CV wouldn't be compulsory under the terms of the licence.) $\endgroup$ Commented Nov 11, 2016 at 13:20
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    $\begingroup$ @Scortchi I vote for courtesy too. An orthogonal dimension is that some reviewers of scientific journals might react negatively to any idea that one was just writing up postings from the internet, regardless of any merits of clarity, cogency or originality. The positive converse is that many postings here, especially from esteemed moderators, are much higher in quality than much peer-reviewed and formally published material on the same topics. $\endgroup$
    – Nick Cox
    Commented Nov 11, 2016 at 13:37

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