Sean Parker has had a hand in some of the Valley's biggest successes. His first company, Napster, took the world by storm, but didn't make Parker rich. His second, Plaxo, just sold to Comcast. And his third, Facebook — well, say no more. Except for the bit about him getting kicked out, according to Mark Zuckerberg's legal testimony, for a cocaine arrest. (Parker characterized the incident as "a misunderstanding.") That and more is covered in the 21 pages Sarah Lacy devotes to Parker in Once You're Lucky, Twice You're Good, new book about Web 2.0. The index page where Parker is listed:

Previously:

• A is for Adelson, who cofounded Digg
• 
  
• B is for Botha, who sold YouTube big
• 
  
• F is for Fitzpatrick, and "hookers and blow"
• 
  
• L is for Levchin, who never goes slow
•