In the ongoing race to online advertising dominance between Google, Yahoo!, Microsoft and AOL, Time Warner Inc.'s AOL unit reportedly will buy internet advertising technology company Quigo to bolster its ad force.

One source familiar with the matter told Reuters reporters the purchase price was approximately $340 million. The company did not disclose financial terms.

Similar to Google's AdSense program, Quigo's technology lets advertisers buy sponsored listings based on keywords or subjects. But whereas advertisers have little say on where Google places their ads, Quigo's AdSonar product lets advertisers place their ads on specific web pages, including pages featuring topics or keywords such as "mutual funds" or "health and science."

"With Quigo, we are putting the final pieces of Platform-A in place," AOL Chief Executive Officer Randy Falco said in a statement, referring to AOL's advertising technology strategy. "We will be able to offer advertisers and publishers the most advanced set of tools, including contextual and behavioral targeting, superior analytics, and access to the largest display network in the marketplace."

The anticipated purchase will add to Time Warner's growing roster of online ad technology firms and is a part of AOL's restructuring plans to transform into a one-stop shop for advertisers.