Is moving self-answers in questions into separate answers under the Community user valid under CC BY-SA?

Question

Prompted by my question at How best to deal with self-answers edited into questions? which was somewhat answered with a link to What to do when OP answers his/her own question in an edit?, which then prompted me to post this question.

Several comments on my Meta.SO question, as well as this answer to the above Meta.SE question, suggests as one of the options:

If OP does not respond within two 2 days. You edit his solution out of his question, and post it as a community wiki answer. This is not a perfect solution but it helps users who run into the question. Be sure to attribute the solution to OP.

However, that answer was posted a good 7 years ago, and time has moved on since then. In particular, we now have CC BY-SA governing attribution. I am not a lawyer, so I would like to know:

Is moving a questioner's self-answer into its own answer, credited to the "Community" user and with attribution to the questioner, valid according to CC BY-SA? I am particularly looking for answers by lawyers and/or those familiar with CC BY-SA, and/or Stack Exchange Inc. employees/representatives.

Answer 1

Yes, but you need to attribute it and link to the original.

CC-BY-SA 4.0 requires you to do the following when sharing licensed material:

• retain the following if it is supplied by the Licensor with the Licensed Material:
  • identification of the creator(s) of the Licensed Material and any others designated to receive attribution, in any reasonable manner requested by the Licensor (including by pseudonym if designated);
  • a copyright notice;
  • a notice that refers to this Public License;
  • a notice that refers to the disclaimer of warranties;
  • a URI or hyperlink to the Licensed Material to the extent reasonably practicable;
• indicate if You modified the Licensed Material and retain an indication of any previous modifications; and
• indicate the Licensed Material is licensed under this Public License, and include the text of, or the URI or hyperlink to, this Public License.

The notices of the license are handled for you by the Stack Exchange platform, and I've never seen an SE post with an explicit copyright notice.

To indicate that you modified it (if you did), you could post the original first, then make any changes as edits after the five-minute grace period is expired. You could also just note explicitly in the answer that you edited it.

That leaves identification and a hyperlink.

To address that, you could start your Community Wiki answer with:

This was originally posted here by OP_name_here

Answer 2

I'm not a lawyer, only a bit familiar with CC licenses (I read them and read a bit of stuff about them).

I agree fully with the answer of Ryan M, it's perfectly valid to take part of other posts and cite them with attribution even in community wiki posts. Just want to add some details here.

The provision for attribution of CC-BY-SA is detailed in section 3(a) of the license. It tells you what information you have to provide in 3(a)1, that you have quite a lot of freedom how you provide it in 3(a)2 and that the original author has the right to request removal of that information from you in 3(a)3.

Obviously the software running this platform won't help you like it does when doing edits (but otherwise it's completely the same mechanism), so whenever you copy parts of other posts in your post (community wiki or not) you must give attribution in any reasonable way. Typically you will do what Ryan M proposed. You don't have to do more.

The fact that it's a community wiki post is not really relevant here. It's just relevant for you. What are “Community Wiki” posts? says that they partly transfer ownership. Not sure if they meant that in a legal sense. I could imagine that users creating community wiki posts still have users as authors, but these users just dissociated according to section 3(a)3 (the right not to be named). But then in the edit history of community wiki posts they are still named and usually you would request that separately so maybe not even that.

Finally, it's probably not relevant here because if you split a post you probably created an adaptation but if you would just copy a whole post without any further ado it could also be just a reproduction instead of an adaptation. In that case it might be wrong to increase the CC-BY-SA version (as the timeline would indicate) because section 3(b), the sharealike part only applies to adaptations. I'm not familiar enough with copyright law to say exactly where the difference between mere reproduction and adaptation really is defined.

See also Is usage of a still frame from a video considered a derivative work/adaptation?. The question is if splitting the answer from a question is an editorial choice and therefore an original work or just a mere abridged reproduction of the original content.