AOL said on Wednesday it would buy Internet advertising technology company Quigo.

AOL did not disclose financial terms of the deal but Reuters reports that the purchase price is about $340 million, citing a source familiar with the matter.

Quigo will be the fourth advertising company AOL has acquired in 2007. Earlier in the year, AOL acquired Third Screen Media, a mobile advertising company, ADTECH AG, an ad serving platform based in Frankfurt, Germany, and TACODA, a behavioral targeting company. In addition, in September, AOL announced the formation of Platform-A, the world's largest digital display advertising platform, which reaches over 91% of the online audience.

"With Quigo, we are putting the final pieces of Platform-A in place. 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." said Randy Falco, Chairman and Chief Executive Officer, AOL. "And by offering advertisers the ability to target ads based on the content of Web pages using Quigo's AdSonar technology, we will be able to maximize the value of publishers' ad inventory."

Quigo employs approximately 100 people and will operate as a wholly owned subsidiary of AOL within the Platform-A organization. Quigo will allow AOL to expand the use of contextual advertising across AOL's own Web pages, as well as its third-party networks.

Quigo lets advertisers buy sponsored listings, much like Google's AdSense, based on keywords or subjects.

The Quigo system also lets publishers control their relationship with advertisers, rather than surrender control to a middleman like Google.

The deal for Quigo comes amid a buying frenzy in the interactive advertising market and follows Google's $3.1 billion pact to buy DoubleClick and Microsoft's $6 billion agreement to buy aQuantive Inc.