Most Americans belong to an online community of some sort. Some share baby photos or funny videos with their friends. Others jabber about the news cycle or bacon.

And then there are those who want to know the natural process that produces Zipf's law or the formal consequences of the Riemann-Roch theorem. For mathematicians, the forum of choice is Math Overflow (which turned one year old on Tuesday), an online community powered by a particular type of software that's profoundly affecting the way researchers communicate and collaborate using the Web.

At a time when Malcolm Gladwell (among others) is questioning the value of the Internet as an organizational platform, Math Overflow is an excellent example of a complex and organized online project. Developed in 2009 by a group of Berkeley grad students and post-docs, Math Overflow was conceived as a question and answer forum for research-level mathematicians. Boasting 2,700 active users ranging from especially bright undergrads to Fields medalists, the basic function of the site is to answer the highly technical questions that crop up in math research.

"Sometimes you come across a problem that you can't solve yourself, but someone else has probably already solved -- if you only knew who to ask," said Anton Geraschenko, a UC Berkeley grad student and one of the minds behind Math Overflow. "Intermediary steps are incredibly important in math, and some intermediary proofs are usually regarded as so self-evident that they're difficult to track down in publication form. But instead of painstakingly having to prove something already taken for granted, you can find the solution or documentation elsewhere. Math Overflow seems like magic because you post a question and 'poof,' you get this answer that's extremely intricate in a short amount of time."