A number of Facebook's familiar features have stemmed from hackathons, such as Timeline, Video and the Like button. Another is Chat. "Chat was a small little project that a couple of people worked on," Keyani says. "They built it just for employees and when it was presented everyone asked, 'Why didn't we think of that?'"

covers consumer technology, social networking and enterprise collaboration for CIO.com. Follow Kristin on Twitter @kmburnham. Follow everything from CIO.com on Twitter @CIOonline and on . Email Kristin at kburnham@cio.com