2. Mark Pincus
Estimated Net Worth: $850 million
Love-him-or-hate-him leader of Internet's most popular gaming site, Zynga, named for his late bulldog. Pincus' fourth startup, it grosses some $500 million from virtual goods and promotions with 7-Eleven, Target, MTV. "FarmVille," "FrontierVille" and "Zynga Poker" are its most popular games.
(Photo: ZUMA Press/Newscom)