A geek hero for his role in co-founding Napster, Parker became a cultural icon thanks to Justin Timberlake's portrayal of him in The Social Network, Aaron Sorkin's Hollywood version of Facebook's foundation.
Parker played a key role in the company's early days, helping Zuckerberg secure financing and structure the company. He briefly served as Facebook's president, but got edged out as Facebook matured and brought on more seasoned executives. He didn't leave empty handed. Parker's Facebook holdings will do what Napster couldn't: make him rich.
NEXT: Facebook's co-founders