1. Sean Parker
Estimated Net Worth: $920 million
Cofounder of Napster and Plaxo, Parker was the Silicon Valley veteran who joined Facebook in 2004 as its founding president and helped it navigate initial funding. He left in 2005 for venture capital but still has a 4% stake. Justin Timberlake plays Parker in the upcoming film The Social Network.
(Photo: Ralph Orlowski/Getty Images for Burda Media)