No. 9: Sean ParkerAge: 33
Net Worth: $2 billion
Sean Parker was one of the founders of Napster, that popular file sharing application that almost brought down the entire music industry. It is considered to be the fastest growing business of all time, amassing tens of millions of users within a year of its introduction. He also served as the first President of Facebook and co-founded Airtime, Causes and Plaxo. He is currently on the Board of Directors of technology firms like Spotify and Yammer.