• by Mark Walsh  @markfwal, October 3, 2008

Facebook co-founder Dustin Moskovitz is leaving the company to start his own company with colleague and fellow engineer Justin Rosenstein, Facebook confirmed Friday. 

"Dustin has always had Facebook's best interests at heart and will always be someone I turn to for advice," said the social network's co-founder and CEO Mark Zuckerberg, in a prepared statement. Zuckerberg, Moskovitz and Chris Hughes launched Facebook five years ago as Harvard undergrads.

Hughes previously left day-to-day operations at Facebook to help coordinate Barack Obama's online campaign.

A Facebook spokesman said Moskovitz's departure was not completely surprising, given the entrepreneurial bent of its founders and top executives.

While details of the new venture were not disclosed, a Facebook note from Rosenstein to friends being circulated online gave some indications. He wrote that he and Moskovitz would leave in a month "to build an extensible enterprise productivity suite, along with a high-level open-source software development toolkit, built for the Web from the ground up."

He added that the new service would be compatible with Facebook. "Our user interface will adopt many of Facebook's conventions, creating a seamless and familiar experience for current Facebook users."

News of Moskovitz's exit comes the same week that Facebook completed the conversion to its redesigned site, unveiled in July. The overhaul was intended to create less cluttered profile pages and a more streamlined user experience.

His departure also follows that of other top Facebook executives in recent months, including Vice President of Product Management Matt Cohler, who Benchmark Capital announced in June would join the Silicon Valley venture capital firm this fall. Chris Cox, who helped develop Facebook's key News Feed feature, will become the company's director of products.

Mike Schroepfer, Facebook's vice president of engineering, was brought on in July from Mozilla Corp. following the departure of CTO Adam D'Angelo.