The Company: Facebook.com connects the college crowd at thousands of schools across the country. It's the seventh most popular site on the Web, with 13 million unique visitors a day. It serves up more than 7 billion page views daily, ranking it second after Google. Next step: Translating success in the college market to the high school and post-grad scenes.
Funding: The company has raised $38 million so far -- a feat that is lore among the Web 2.0 crowd. Zuckerberg shrewdly negotiated a $100 million valuation during the first round of funding and a clause that leaves him in charge as long as he wants. In a second round of funding, that valuation soared to $500 million.
Background Check: Zuck, as he's called, wrote the software for the site in his dorm room at Harvard as a way to rate the attractiveness of students -- a prank that landed him in the Dean's office. He reworked it as a way to connect with classmates and it caught fire.