I'm personally quite bothered by the statement on the MathOverflow main page (when not logged in) that "MathOverflow is a question and answer site for professional mathematicians." It seems both false and unnecessarily exclusive, even pretentious. I much prefer the terminology, used elsewhere on the site, of "research level mathematics," e.g. "MathOverflow is a question and answer site on research level mathematics." That sentence's grammar is a bit clunky, and perhaps that's even why the term "professional mathematicians" got used in the first place. But I'm sure we can think of a more inclusive tag line which still reads well.
Again, whatever the alternative should be, I find it highly distasteful and in fact, problematic, that we are suggesting that one should be a paid mathematician in order to use the site -- thereby, on the face of it, rejecting even well-informed and competent amateurs, who certainly can appreciate the beauty and interest of the subject as well as we can. Does anyone else in the community share these views?
Please feel free to edit the question if its wording is problematic, clunky, or too argumentative. Thank you!