Sean Parker got famous and made the RIAA really grumpy and litigious in the process by creating Napster back in the day. He also founded Plaxo, an online rolodex to help people keep track of changing contact info in their networks.
And in 2007, Parker also cofounded Facebook Causes, which has 90 million users. Parker was pushed out of his position as Facebook President in 2006 after being arrested for cocaine possession. You should totally read this Vanity Fair profile of him.
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