AOL, which is owned by Time Warner, has announced that it has bought buy.at, an online affiliate marketing network.

According to Reuters, the move is part of a wider scheme to increase its internet advertising operations.

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, explains the news service.

The acquisition is AOL's fifth in a year, and comes a day ahead of Time Warner's Q1 financial report, during which investors hope new chief executive Jeffrey Bewkes will discuss a plan to restructure.

This is seen to be more pressing now by investors because of Microsoft's proposed bid to buy Yahoo.

Also - Time Warner shares have fallen as much as 12% since the beginning of the year as a result of a broad market-wide sell-off following fears that an economic recession could hurt advertising sales.

Bewkes is expected to move AOL even further towards becoming "a one-stop shop" for online advertisers, says Reuters.

AOL has not revealed how much it has paid for its latest acquisition.