Early employees at ultra-successful tech startups tend to go on to found their own companies. They're young, flush with cash, and they've been tricked into thinking that startups often succeed. In that, Facebook's employees are no different from their predecessors at Google and Paypal. But The New York Times' Verne Kopytoff notes that there is one odd thing about the current crop of ex-Facebookers: they all left before their company went public. (Facebook remains privately held, of course.) That doesn't mean they couldn't cash in their options, though, thanks to a bustling private market for the company's shares.

[A] number of Facebook's early employees are giving up their stable jobs, free food and laundry service to build their own businesses. Many of them are leaving as wealthy, either on paper or after cashing in their ownership stakes to do what they say they like best: start companies.

Dustin Moskovitz, 26, who co-founded Facebook with his Harvard roommate Mark Zuckerberg, left his job on Facebook's technical staff to create Asana, which makes software that helps workers collaborate. Another Facebook co-founder, Chris Hughes, also 26, has started Jumo, a social network for "people who want to change the world." Dave Morin, formerly the senior platform manager, is building Path, a still-secretive venture, while Adam D'Angelo, who was Facebook's chief technology officer, and Charlie Cheever, another senior manager, set off in 2008 and 2009 respectively to start Quora, a question-and-answer site. More than half a dozen start-ups can trace their origins to Facebook alumni.

The departures follow a familiar pattern among other Silicon Valley successes like Yahoo, eBay and Google. After amassing fortunes, early employees start walking out the door. PayPal's have gone off to start YouTube, Slide and Yelp, and staked Facebook. They are known as the PayPal Mafia. Google's former employees are called Xooglers. Mr. Morin, who left Facebook this year, offered this suggestion: Facebook Society. "We're social," he explained.

But the Facebook Society is slightly different from the earlier alumni associations. The other serial entrepreneurs usually cashed out before resigning.

Read the full story at The New York Times.