This article is more than 10 years old. Perhaps the most dramatic example involves Mark Zuckerberg and Dustin Moskovitz, the co-founders of Facebook and two of the world’s youngest billionaires.

Dustin Moskovitz left Facebook in 2009 to start his own company, Asana, and he hasn't said much publicly about either project since. Since he's a pretty active user of the question-answer site ...

Now Moskovitz is a part of a group casually known as the “ Facebook Mafia,” a collection of early (now ex-) employees building new services, like he is with enterprise collaboration company Asana.