The New York Times reports that Facebook has finally wrested the Atlas ad serving system from Microsoft in a deal neither party is willing to describe in detail. Such a deal has been rumored for months. Facebook's unsophisticated advertiser front end has been seen as a liability, as building out a real trafficking and targeting platform for advertisers would take a significant amount of time. Microsoft, on the other hand, bought Atlas and a few other attending properties for more than $6 billion in 2007 - a price that even in those breathy times seemed large.

A Facebook official blogged the news this evening.

Microsoft has since taken a roughly $6 billion write-down on the properties, although the purchased assets and written-down assets do not perfectly line up. Selling Atlas for a significant sum would go some ways to saving face for the Redmond giant. That terms have not been disclosed may imply that the sum wasn't as significant as shareholders might have liked.

Talk of a deal started last summer, not long after Microsoft's Bing search engine blog wrote about how well its search engine melds with Facebook.

Analysts focusing on Facebook since its recent initial public offering have been concentrating on the idea that an ad serving system such as Atlas could allow Facebook to leverage the intimate knowledge it has of its users to target not only Facebook media, but also avails from other sites and systems. That prospect of taking Facebook's greatest asset and spreading it across the web gives rise to expectations that might be hard to manage. Analysts covering Microsoft have generally been watching for the deal as a simple asset sale.