Time Warner's America Online arm is to pay $435m in cash to acquire Advertising.com, a privately held supplier of interactive marketing services.
AOL's move follows up on Time Warner's pledge to bolster the fortunes of its troubled online division.
'Online advertising is showing very strong growth across the industry, and the acquisition of Advertising.com underscores AOL's determination to strengthen its competitive position,' said Jonathan Miller, chairman and chief executive of AOL.
Time Warner is the world's largest media and Internet company. But AOL, while the biggest in the online field, has been struggling with slow growth while also seeing subscribers defect in large numbers in the face of competition from rivals providing broadband Internet service.
Advertising.com accumulates data from web sites, search providers and e-mail publishers to give advertisers a wide-ranging group of online marketing alternatives.
AOL said its advertising inventory, combined with Advertising.com's network, would enable advertisers to appeal to more than 140 million internet customers and allow AOL to offer advertisers more customised services.
