If there is some useful response to a question, can I cite it to an academic journal?
$\begingroup$ Do you mean you want to answer a question here with results from an academic paper and refer to this paper in your answer? $\endgroup$– AndyMay 4, 2014 at 16:17
4$\begingroup$ @Andy, I think it is the opposite. He/she is referring about using content retrieved from SE on an academic paper and give the credit (by citing) to the author of question/answer. $\endgroup$– Andre SilvaMay 4, 2014 at 18:49
1$\begingroup$ Oh okay, I actually thought that but it seemed a bit too idealistic to be real. I mean, the temptation is great to use the knowledge acquired on CV in a paper and pretend it's one's own work. After all what would a referee think if I thank CV user589646 in my first-page footnote? But of course it would be appropriate to somehow acknowledge other people's input. I don't see though how this can work given the anonymity that we have here? $\endgroup$– AndyMay 4, 2014 at 19:01
9$\begingroup$ This has come up on the math site, see What is a good standard for publishing a reference to a stackexchange thread? for one example. There are a few more if you look as well, e.g. Do I cite mathstackexchange in my paper? and associated threads in the comment. $\endgroup$– Andy WMay 4, 2014 at 20:56
12$\begingroup$ Nothing here prevents or prohibits your citing material in a submission to an academic journal. The real question is what happens the other end. As a reviewer and journal editor, I know my own attitudes: I would much prefer a citation to a book or journal article for anything standard, but I would be happy to consider an argument for citing really original material. Some of the best posts here (e.g. those by @whuber) cover points not obviously covered, or covered so well, in the academic literature. You will find a bias in some quarters against citing anonymous material. $\endgroup$– Nick CoxMay 4, 2014 at 23:45
Continuing @Nick Cox's thoughts in the comment thread, my inclination both as a writer and reviewer would be that if you have encountered useful material on CV that you believe to be original, then include an account of it in your paper (as a brief appendix if you must) and acknowledge its original source. That makes you responsible for it, which removes the problem of relying on potentially unreviewed anonymous posts on the Internet, while complying with the scholarly tenet of recognizing your sources.
If you need a posted image, treat it in the usual way: contact the owner for permission to re-use it. I periodically get requests from publishers in this regard and routinely grant them.
citing a question or an answer for a hypothesis being proposed should not be a problem. I have found some real good answers - original ones too. Citing these answers as a cross validation could be helpful and desirable. But, there must be appropriate guidelines and screening by the experts in the relevant field.