• by Gavin O'Malley  @mp_gavin, February 6, 2008

To bolster its advertising infrastructure, Time Warner Inc.'s AOL has purchased an online affiliate marketing network named buy.at.

To build its overarching Platform-A advertising unit, AOL's acquisitions this past year have focused mainly on ad serving. Buy.at, meanwhile, is expected to give AOL a more direct relationship to online retailers.

Buy.at is a network for advertisers to pay its member Web publishers based on user actions. The network opens the door to an e-commerce platform where online merchants can sell their products through third-party sites.

The purchase comes less than a week after Microsoft's $31-per-share unsolicited offer to buy Yahoo, which has sparked acquisition rumors for AOL. It also came a day ahead of Time Warner's first-quarter financial report, which is expected to include guidance on the future of AOL. Financial terms of the deal were not disclosed.

Targeting the largest marketers and ad agencies, AOL established Platform-A late last year to encompass its various ad networks, naming Curt Viebranz, former CEO of Tacoda and a one-time Time Inc. executive, to lead it. Platform-A works closely with Advertising.com, the AOL unit that matches buyers of online advertising to thousands of Web sites with extra ad space to sell.

"This acquisition further enhances our Platform-A advertising offerings by enabling us to offer a new set of advertiser and publisher products, while also supporting our international strategy," AOL Chairman and CEO Randy Falco said in a statement.

With offices in London and Newcastle in the United Kingdom and in New York, buy.at employs about 70 people, and counts some 200 e-commerce businesses as its clients.

Platform A encompasses Ad.com, the direct-response network AOL acquired in 2004; Tacoda, the behavioral ad network it recently bought for $275 million; the video ad network named Lightningcast; Third Screen Media, a mobile ad network, and AdTech AG, an international online ad-serving company based in Frankfurt, Germany.

The reorganization came amid criticism that AOL has so far failed to meet some media buyers' expectations, and after parent company Time Warner released slower ad growth numbers for AOL--news that sent its stock price down 3%.