As Facebook prepares to file its IPO paperwork, one of the men who was there in the social networking site's early days won't be profiting quite as much as his former roommate, Mark Zuckerberg.


Instead of dropping out of Harvard to help run the company, Joe Green completed his college education. Green and Zuckerberg created the proto-Facebook website called "Facemash," a site that allowed Harvard students to rate whether their peers were "hot or not." Threatened with expulsion, Green elected not to participate in the launch of what would become Facebook.


ABC News called this "a $400 million mistake" during a profile of Green on "Good Morning America" on Jan. 30.


Instead, Green graduated, followed his passion for politics by working on John Kerry's 2004 presidential campaign, and went on to found Causes, one of Facebook's biggest apps, which allows users to put the social network to good use for social and political good. Causes launched in 2007, and in 2008, Bloomberg Businessweek named Green one of "tech's best young entrepreneurs." More recently, he was named for Forbes Magazine's Top 30 Under 30.


"The way to get people civically engaged, not just during the election but throughout the year, is to tap into Facebook and let them do it with their friends," Green told ABC.


He says Causes has helped users to raise $50 million for 50,000 charities.


Green won't be left out in the cold by Facebook's initial public offering or IPO. He owns an unspecified amount of the company's stock, which will no doubt net him a small fortune when it goes public. Not $400 million worth, but maybe enough to keep him and Causes moving forward.


Watch Green on "Good Morning America":


Causes founder Joe Green doesn't regret not helping Mark Zuckerberg launch Facebook
He bailed out of building Facebook, what has been called a $400 million mistake.