As far as I can say, some users of math.stackexchange also participate in editing wikipedia articles.
In comment to this MO question a user mentions editing a part of wikipedia article relevant to the question.
Questions of the type: Wikipedia claims this, I do not understand, can somebody help? are, in my opinion, perfectly valid mathematical questions, so there should be no problem with them.
What about questions, where the motivation of the OP is his effort to improve wikipedia article? Examples:
Wikipedia article on A contains the claim that B holds if and only if C. I believe that this is wrong for the following reasons..... However, I am not an expert in this area, could someone tell me whether I made a mistake or the wikipedia article is wrong?
Wikipedia article on A contained the claim that B holds if and only if C. I believe that this is wrong and I did my best to correct the article; namely that B holds if and only C and D. However, I am not an expert in this area, could anyone check my work?
User XYZ changed the wikipedia article about A in the following way.... I think this is not correct. Could someone confirm my suspicion?
Wikipedia article about A contains no references for the claim that B holds if and only if C. I was not able to locate such references myself. Is anyone aware of some references confirming this claim?
I believe that the primary place for asking such questions should be at wikipedia, probably somewhere in the scope of WikiProject Mathematics - although I am not exactly sure where, but I was wondering what the users of math.SE would think about posting such a question here.
If such questions are not recommended here, would it at least be appropriate to ask such a thing here after trying at wikipedia and not getting an answer after some longer period?
Perhaps I should add, that I am asking this because I intended to ask the question about an unreferenced definition in wikipedia article, i.e. the last example. (But I will do some more searching before.) I was am not sure, whether to ask it here or at wikipedia.
My motivation is that I would like to know this reference for my study - so it's not the case that the reason for asking is solely an effort to improve the wikipedia article. But if I would get a good answer here, I would probably go on and edit wikipedia article.
EDIT: Another question(s) of this kind: