Update: AOL has officially announced it: it has bought the mobile ad firm, closing months of due diligence and contract negotiations. More than 100 mobile Web publishers and major wireless carriers participate in the TSM network, the companies said. Microsoft recently bought French mobile ad firm ScreenTonic.

Original post: You’re reading it here first .. We have learned that AOL is expected to announce this morning that it—finally—has closed a deal to acquire Third Screen Media, the mobile ad network and mobile ad-serving platform provider. In February we confirmed they were in talks about this. TSM will operate as a wholly owned subsidiary of AOL’s Advertising.com division, and will be continue to be headquarted in Boston. Financial terms of the deal were not disclosed.

Clickz: One week prior to the acquisition announcement Third Screen Media released statistics from its ad network. It serves more than 225 million monthly advertising impressions across more than 185 mobile content sites including AccuWeather, Boston.com, Fox News, the Gannett network of newspapers, Maxim, Wapipedia, and WWE.

• Third Screen Media Looks For A Buyer; In Talks With AOL
• Third Screen Looking To Raise Funds; No Sale To MSFT
• Third Screen Media Secures $5 Million in Series B Funding