AOL has snapped up mobile ad network Third Screen Media, reports AdAge.

The acquisition comes after a long period of rumors that the firm was triggering acquisition interest from both AOL and Microsoft.

AOL's purchase is likely powered by Third Screen's capabilities in delivering ads in text and a variety of other formats, including downloads. Much of its business comes from the sale of banner ads, highly valued by brand advertisers.

Omar Tawakol of Medio Systems points out the banner ad function makes Third Screen appear a helpful addition to the growing ad arsenal AOL is slowly nursing, which includes Advertising.com.

Third Screen still suffers from small reach numbers - at least in the eyes of advertisers - but it is growing quickly as it expands into more wireless networks.

Anne Baker, VP of Marketing at Action Engine Corp., says this and other recent moves in the mobile market should be a signal that ads are coming in force. Baker points out, however, that technology needs to be in place to make sure the ads are delivered in a way that doesn't turn off users.

AOL will integrate Third Screen's operations into Advertising.com but the firm will still be headquartered in Boston.