Why does Stack Exchange use this weird “cc-wiki” euphemism instead of calling the CC-BY-SA by its real name?
This is a bug report disguised as a question. As in: please fix the footer.
Dunno when exactly, but it was fixed and rolled out to all sites:
As far as I can tell, "cc-wiki" is an old working name for the license that eventually became CC-By-SA 2.5. According to an article in The Wikipedia Signpost on March 25, 2005:
"Last Thursday, Creative Commons introduced a beta version of its new license designed specifically for wikis, in conjunction with Lawrence Lessig's introduction of a wiki to help draft an updated version of one of his books.
As Lessig explained it, with the new license, which has been given the designation of CC-Wiki, "rather than requiring attribution back to the copyright holder, [the license would] require attribution back to either the copyright holder or a designated entity." The designated entity would presumably be whatever organization controlled the wiki. Lessig characterized it as a newly branded version of the attribution/share-alike (CC-by-sa) license, rather than being an entirely new license."
The "new license" link in the quoted text takes you to
http://creativecommons.org/drafts/wiki_0.5, which, as of this writing, redirects to
http://creativecommons.org/licenses/by-sa/2.5/. According to archive.org, the "cc-wiki" link in the Stack Overflow footer has always linked to the CC-By-SA 2.5 license page since the public beta in 2008, until it was changed to point to the 3.0 version in April 2011.
So, to answer your literal question, apparently the "cc-wiki" designation is an obsolete synonym for CC-By-SA 2.5 that was adopted by SO in its early days and never updated, not even when the license version was changed. IMO, it should be fixed, if only to avoid confusing people.
Not expert in this field of licence and attributions, but looks like Jeff was under the impression those two are the same, as he wrote in the Attribution Required blog post:
From quick Google search looks like he wasn't the only one, but it's not really common though and I couldn't find the origin.