Facebook Inc said on Thursday it struck a deal to buy advertising technology from Microsoft Corp that should help prove the effectiveness of its customers' advertising.

Under a long-rumored transaction, Facebook will purchase the Atlas Advertiser Suite, an ad serving, management and measurement platform that Microsoft took over through its $6.3 billion acquisition of aQuantive in 2007. Facebook did not say how much it paid for the technology.

Unable to make it work for its own purposes, Microsoft wrote off $6.2 billion of the aQuantive deal's value last year.

(Reporting By Alexei Oreskovic and Bill Rigby; Editing by Leslie Gevirtz)