TL,DR: Yes, it does. Only in a small minority of cases — but Stack Exchange must nonetheless make sure that that small minority of cases is treated correctly (in the same manner that spending 364 days per year without committing a burglary does not make it ok to spend one day a year committing burglary).
Stack Exchange operates under United States law. Title 17 of the U.S. Code, and in particular chapter 1, applies.
The content of posts is Subscriber Content as per §3 of the Stack Exchange terms of service.
all Subscriber Content that You contribute to the Network is perpetually and irrevocably licensed to Stack Exchange under the Creative Commons Attribution Share Alike license.
Clause 4c of the Creative Commons license recognizes the right of the author to be attributed:
If You Distribute, or Publicly Perform the Work or any Adaptations or Collections, You must (…) keep intact all copyright notices for the Work and provide, reasonable to the medium or means You are utilizing: (i) the name of the Original Author (…); and (iv) , consistent with Ssection 3(b), in the case of an Adaptation, a credit identifying the use of the Work in the Adaptation (…). (…) in the case of a Adaptation or Collection, at a minimum such credit will appear, if a credit for all contributing authors of the Adaptation or Collection appears, then as part of these credits and in a manner at least as prominent as the credits for the other contributing authors.
The license does not define who must be considered an author in cases where a work is the product of a collaboration.
US copyright law applies to “works of authorship”, and defines the rights of “authors”. These terms is not defined in the law, and thus defined by jurisprudence.
17USC §101 does define “derivative work”, stating that “a work consisting of editorial revisions, annotations, elaborations, or other modifications which, as a whole, represent an original work of authorship, is a ‘derivative work’”. 17 USC §103 adds that “the copyright in a compilation or derivative work extends only to the material contributed by the author of such work”, which does not help in defining whether a contributor can be considered an author.
The article “Defining “author” for purposes of copyright by Russ VerSteeg presents the main views regarding how a contributor to a work gains authorship status. Emphasis is mine.
- “As a general rule, the author is the party who actually creates the work, that is, the person who translates an idea into a fixed, tangible expression entitled to copyright protection.” (Justice Thurgood Marshall, in Community for Creative Non-Violence v. Reid, 490 U.S. 730, 737 (1989).)
- “A collaborative contribution will not produce a joint work, and a contributor will not obtain a co-ownership interest, unless the contribution represents original expression that could stand on its own as the subject matter of copyright.” (Paul Goldstein, Copyright: Principles, Law, and Practice § 22.214.171.124, at 379 (1989).)
This is the majority view. VerSteeg's article goes on to present minority views (upheld by some US courts) which have a broader definition of authorship, requiring a lesser contribution.
Credit to contributors
A vast majority of edits on Stack Exchange are of an editorial nature and thus do not pass the Marshall-Goldstein test: the contribution of the editor cannot stand on its own. For example, spelling and grammar corrections, improvements in presentation and formatting, even the correction of mistakes or the writing of a new title are not original expressions that could stand on their own.
However it does sometimes happen that an editor makes an original contribution that could stand on its own. For example, it does happen that someone adds a figure or original photograph to illustrate a point, or a code sample, or adds updated information to follow technological evolution, or clarifies a point where the original author's explanations were unclear. All of these cases are both legitimate edits according to Stack Exchange's editing policy (“include additional information only found in comments”, “add updates as the post ages”, “add related resources”, “clarify the meaning of the post”) — and in the case of Community Wiki posts, edits could even legitimately go beyond that.
Such contributors must be attributed as such as per the license that the Subscriber Content is under.
Misattribution of edited content
The user name indicated at the bottom of a post indicates the author of a post. If a post lacks a revision history, this indicates that the author is the sole author of the post. In case the post had other contributors, this is a misattribution which is potentially punishable under slander law. In some cases, this may also fall afoul of clause 4d of the Creative Commons license:
You must not distort, mutilate, modify or take other derogatory action in relation to the Work which would be prejudicial to the Original Author's honor or reputation
Attribution when the original poster has no account
Even attribution to the original poster is not always done correctly. If the author of a migrated post does not have an account on the target site, then only the author's account's display name is mentioned in the migrated post. I believe that this does comply with the letter of the Creative Commons license, even though it is arguable that authors on Stack Exchange are not defined solely by their display name (which is not unique) but also with their profile (which the display name always hyperlinks to in the interface, as long as the author has not removed their profile, except in the case of migrated posts). However, this violates the attribution requirements, which mandate to “hyperlink each author name”. (I am not sure whether these attribution requirements are opposable to Stack Exchange — the wording in the terms of service is unclear on that point.)
If a migrated post had more than one author, then a list of the names of all co-authors is sometimes legally required. A simple way to achieve this objective is to migrate the revision history of every post.
P.S. Since US law was mentioned… it should be abundantly clear, but I'll state it explicitly anyway. I am not a lawyer. I am not a judge. I am not a law professor. I am some guy on the Internet. So this post is not a legal opinion or legal advice, it's the opinion of some guy on the Internet. (I've never been convicted for burglary though, that must count for something?)