All contribution on Stackoverflow made by an user is under a Creative Commons Share Like-Alike License. Although, there are few limitations to it.
[...] (a) infringes, violates or otherwise interferes with any copyright or trademark of another party,
(b) reveals any trade secret, unless Subscriber owns the trade secret or has the owner’s permission to post it, [comment: very vague, trade secrets are a political theme]
(c) infringes any intellectual property right of another or the privacy or publicity rights of another,
(d) is libelous, defamatory, abusive, threatening, harassing, hateful, offensive or otherwise violates any law or right of any third party,
(e) contains a virus, trojan horse, worm, time bomb or other computer programming routine or engine that is intended to damage, detrimentally interfere with, surreptitiously intercept or expropriate any system, data or information, or
(f) remains posted after Subscriber has been notified that such Subscriber Content violates any of sections (a) to (e) of this sentence [...]