Schewek wrote:
Why not add a "from <chose your date> the license is changed to...", and ask all contributers to sign on a page if they retroactively agree, and theoretically one could filter out all articles not covered and rewrite those if necessary.
Given the thousands of Wikipedia contributors, this is impractical.
We can, however, do this for Wikibooks, but only if it happens early. If we ignore the licence issue now and just use the GNU FDL, then it will be equally impractical for Wikibooks.
-- Toby