Who is Sean Parker? He was a founder of Napster, Plaxo and Facebook — three of the internet's most popular social media sites. Napster revolutionized the online distribution of music; Plaxo helps users share their address data; and Facebook is the place college students go online to publish and flirt. One acquaintance of Sean Parker says he's the Jim Clark of the current generation of web entrepreneurs: instinctive, difficult, and with a triple of successes, already, at the age of 27. Jim Clark was a founder of Silicon Graphics, the computer maker, and backed both Netscape and Healtheon.

Why is Parker in the news? He's working on something new, probably, given his track record, a social network service of some sort. But the main reason Parker's attracted the attention of Valleywag is that he's dogged by personal rumors as lurid as Larry Ellison's. Parker, trying to clear up one particular story, says he was never apprehended for cocaine possession, but there was a misunderstanding of the highest order which underlies the rumor of drug use.

It's his life: why should we care? Valleywag couldn't care less if Sean Parker put the entire proceeds from a Facebook sale into the Colombian economy. But there is a more serious business angle to the story. Mike Moritz, Silicon Valley's leading venture capital investor, was on the board of Plaxo, and by some margin its most powerful member. Sean Parker was forced out of the company, abruptly. The circumstances of that departure have never been disclosed. No wonder the mystery encourages speculation.

If Sean Parker's such a star, why has nobody heard of him? Because Sean Parker tends to crash out of his ventures even more rapidly than Jim Clark ever did. He had to leave Napster after brash emails which weakened the company's case against the music companies which eventually destroyed it; Parker was locked out of Plaxo, and any inquiries about him were referred to the company's lawyers; and he has been written out of the history of Facebook.

Facebook? I thought that was Mark Zuckerberg's creation. It was, but Parker played a key role, and he's an important shareholder. Parker could make $100m if the company is sold, Numair Faraz writes. "Sean Parker is the one who convince Mark Zuckerberg to turn Facebook into a real business, to move to Palo Alto, to take the seed money from his friend Peter Thiel (who gave him the generous terms needed to keep control of the company even after the VCs got involved), to hire former Napster employee Aaron Sittig to redesign Thefacebook into what we see on the site today; it was Parker who obsessively negotiated with the owner of facebook.com to buy the domain, as the "the" in thefacebook.com annoyed him to no end."