I'm interested in knowing either or both:

  • How does Creative Commons-wiki Share-Alike compare to GPL as it pertains to Stack Overflow?
    (since "cc-wiki share alike vs GPL" is googlable and there are CC and FSF opinions, it would be nice to understand what is consensus about policy here if any. I don't get the relevant difference. I always thought GPL preserves attribution and ensures continued downstream freedom to use the code thereby produced. FSF obviously promotes GPL for code over CC Share Alike.)
  • Should questions or community wiki postings be subject to close/delete for including original code the author claims copyright on and GPLs?

Either would be relevant, both for me and others who might wonder about the question as posted.

  • 1
    Removing the reference to a previous bad experience (it isn't relevant) and clarifying your question could help. Which of those two are you asking about? Don't make us guess, just ask about what concerns you.
    – Gnome
    Commented Jul 15, 2010 at 5:21
  • @Gnome Ok, done :-)
    – Paul
    Commented Jul 15, 2010 at 5:26

3 Answers 3


How does cc-wiki share-alike compare to GPL as it pertains to Stack Overflow?

AFAIK, CC-BY-SA is compatible with the GPL; however, SO's attribution requirements may be slightly more restrictive than the GPL. (You can't mix more restrictive conditions with the GPL.) This requires closer scrutiny by someone more knowledgeable in licensing. Additionally, this constraint is unique to SO, so generic CC vs. GPL discussion may not apply.

Should questions or community wiki postings be subject to close/delete for including original code the author claims copyright on and GPLs?

If the author holds the copyright, they can post it under different terms regardless of whether it is also available under the GPL (i.e. on another site). By posting it on SO, the license mandated by SO applies. If you feel something has been posted incorrectly, you can comment asking for clarification or flag for moderator attention.

If someone posts their code on SO and insists that SO's license doesn't apply, then the code should be removed. I've not yet seen this situation on SO. Technically, I believe the code could be kept, but I'm not sure how that interacts with the creator's moral rights (which CC emphasizes) and removing it should be the least controversial solution. However, not all code is copyrightable (it's a grey, subjective area that can only be definitively answered by a court on a case-by-case basis).

  • Having looked around a few more questions, I like your answer and think it makes sense. I have done exactly what you mentioned in your last paragraph, and would only mention that I doubt I'm the first or the last... and that licensing of original works should be based on an informed meeting of the minds. The question of whether a court would apply a "meeting of the minds" test or an "offer-acceptance" test to determine whether SO's license applied is one that won't ever need to be played out. I think people here ultimately do respect moral rights. Thats what a meritocracy is.
    – Paul
    Commented Jul 15, 2010 at 6:14

Small enough snippets may fall under fair use (we are after all reviewing or criticizing) rendering the license issue moot, and throwing it into the realm of copyright law.

Maybe not a good thing, now that I thing about it.


Given that it is reasonable for someone to use any code on SO as part of their product, there should be no code covered by GPL on SO. As otherwise the risk is too great! By putting code on SO you are putting it in the public domain and you can’t do that with GPL code.

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