I wrote an answer here - https://graphicdesign.stackexchange.com/a/15603/3327 edited it to fix some typos, and was surprised to see it had turned into a "Community wiki" seemingly on it's own (the question isn't one).
I've used SE for over a year and I still don't really understand what these are (and I really don't understand why the "Community wiki" text isn't a link to a help page that explains them...). I think it's something like disowning an answer so that any random user can edit it, sort of like saying "help me keep this time-specific information up to date" I think. I certainly didn't intend to make it one, it's a pretty normal answer.
I saw before that questions and answers turn into these if the author edits them loads of times - but I just edited once or twice to fix some typos.
Any idea why it changed ? Can I change it back?