Facebook, the half-a-billion-dollar kid - MarketWatch

"Mark Zuckerberg, who started the Facebook -- essentially an online student directory -- while he was a sophomore at Harvard in 2004 -- just received funding for quite a nice valuation. Zuckerberg, as many of my readers might recall, left Harvard to become an entrepreneur.
Facebook, which now has more than 7 million registered users, recently received $25 million in venture funding from Greylock Partners, of San Mateo.
The valuation for the private firm was $550 million, a source close to the deal told me. "