The Socialite

Mark Zuckerberg
facebook.com

In February, 2004, Mark Zuckerberg and his Harvard roommates launched a social networking site for the school's students. Facebook quickly spread to Stanford, Columbia, and Yale. That year, Zuckerberg moved to Silicon Valley for the summer and then made his stay more permanent, dropping out of Harvard. By the following spring, he had expanded Facebook to more than 800 college networks. Two years later, Facebook opened the floodgates to let anyone join. At last count, there were more than 41 million active users, with membership rapidly spreading beyond teens and twentysomethings, evolving into a business and social tool for adults. Throwing even more fuel on the fire, Zuckerberg recently opened the platform to outside software developers, who've already responded with more than 3,000 widgets to integrate other Web sites with Facebook's pages.