Silicon Valley strategist and former Facebook president debuts as a billionaire based on the surging value the social networking site. His reported stake: just under 3%. At 19, the serial entrepreneur co-founded Napster in 1999, the peer-to-peer music sharing service that brought free music to the masses, but quickly collapsed under piracy allegations. Still, the disruptive technology helped trigger the record industry's precipitous decline. Parker joined Facebook in 2004. Recently made more famous after being played by Justin Timberlake in the Oscar-winning film "The Social Network." He's currently a managing partner at Founders Fund, a venture capital firm that invests in tech companies. Diving back into digital music with an investment in Spotify, the popular European music subscription service that hopes to launch in the U.S. sometime this year. In April 2016, Parker pledged $250 million to launch a research initiative through the Sean N. Parker Foundation, on cancer immunotherapy at six academic institutions. Sean N. Parker Foundation was started with $600 million in June 2015 to fund life sciences, global health and civic engagement.