MathOverflow – Get answers to your mathematics questions
Back in August 2008, Joel Spolsky and Jeff Atwood launched a question and answer site aimed squarely at programmers and it has been a massive hit. Called Stack Overflow, the site currently contains over 330,000 questions and answers covering pretty much every aspect of programming you care to mention from What IDE to use for Python through to smart pointers in C++ and everything in between. With a userbase running into the thousands, you can be sure that someone, somewhere will know the answer to your programming question no matter how obscure. All this and yet, in true internet tradition, it won’t cost you a penny.
Well, time moves on and Stack Overflow spawned other sites based on the same web technology. Server Fault, for example, is aimed at system administrators and finally, to complete the trilogy, we have Super User which is geared towards general computer enthusiasts. Although neither of these have been as popular as the original programming site (Server Fault currently has 17,000 questions and Super User has just over 12,000) they are still very useful resources. More importantly, they demonstrate that you can use the Stack Overflow technology to build any community question and answer site.
I guess it was inevitable that someone would eventually build such a site for mathematics. Math Overflow is currently in the beta stage of development and only contains just under 400 questions at the time of writing but it has potential. It just needs a bigger audience, so head over there and get questioning.
I guess you could think of it as a people-powered version of Wolfram Alpha!