UPDATE 1-AOL buys online marketing network buy.at

(Explains what buy.at does, background on AOL's other purchases)

By Kenneth Li

NEW YORK, Feb 5 (Reuters) - Time Warner Inc's (TWX.N: Quote, Profile, Research, Stock Buzz) AOL said on Tuesday it has purchased buy.at, an online affiliate marketing network, as part of a strategy to bolster its Internet advertising operations.

AOL did not disclose financial terms.

Buy.at is a network in which advertisers pay its member Web publishers only when a visitor to the site takes an action in response to an ad, such as making a purchase.

News of the purchase, AOL's fifth in 12 months, comes a day ahead of Time Warner's first quarter financial report, during which investors hope newly appointed Chief Executive Jeffrey Bewkes will discuss a plan to restructure the media conglomerate.

Microsoft's surprise $31 per share offer to buy Yahoo Inc (YHOO.O: Quote, Profile, Research, Stock Buzz) last Friday has heightened urgency on figuring out a plan for its smaller rival, AOL.

Time Warner's plans are likely to include a strategy to spin off its 84 percent ownership of Time Warner Cable (TWC.N: Quote, Profile, Research, Stock Buzz) and what it has in mind for the future of AOL, Wall Street analysts said.

The one-time online king that served as the training ground for generations of U.S. Internet users has been restructured to focus on being a one-stop shop for online advertisers.