Net Worth: $1.6 billion
Sean is a strategist who co-founded Napster, Plaxo, and Causes and was also a part of Facebook. Napster was a peer-to-peer music sharing service that brought free music to the masses. But it didn't last long owing to allegations of piracy. In 2002, Parker launched Plaxo, an online address book and social networking service.
He's currently a managing partner at Founders Fund, a venture capital firm that invests in tech companies.