Rumor has it that Facebook is working on closing a deal with Microsoft to buy the latter's ad-serving business. Microsoft originally acquired the Atlas ad-serving platform as part of its $6 billion acquisition of aQuantive back in 2007 and has been trying to sell it for a while now.

AdAge is reporting that a deal between the two could come as early as next week with the price being somewhere south of $100 million. Rumors of the acquisition first surfaced back in December. Of course, spokespersons for both companies have declined to comment on the possible deal.

An acquisition of Atlas would prevent Facebook from having to reinvent the wheel for a third-party advertising network. It's a logical step for Facebook to start a third-party ad network, so this acquisition could fit perfectly into their plans.

For now, this is just a report, so be a bit skeptical until more information is known.