Could stackoverflow.com work for other fields?
KevBurnsJr: as a site? sure.as a business? hard to tell.Yahoo Answers holds the potential to encompass every use case for StackOverflow and all your offshoots.  However, I sincerely believe that the added context that a site like StackOverflow provides (being that it's curated specifically toward programmers) does provide real value.  That sort of context injection could certainly be carried over to other verticals (provided the sites can attract seed contributors and curators).