Hopping on the latest interactive marketing trend, Time Warner's (NYSE:TWX) AOL is acquiring behavioral targeting specialist TACODA.

Terms of the deal were not disclosed, though this morning's Wall Street Journal pegs the price between $250 million and $300 million. TACODA works mostly with large-brand advertisers, penetrating roughly 80% of the online market by serving up relevant ads through a network of more than 4,000 high-traffic third-party websites.

Behavioral targeting? It's a buzzword phrase that you'll be hearing a lot more of in the future. Unlike conventional ads that show up on any given site -- or even the contextual marketing approach that has been mastered by Google (NASDAQ:GOOG) and Yahoo! (NASDAQ:YHOO) in serving up ads based on a page's content -- behaviorally targeted ads take into account the actual user's demographics and surfing habits.

This is a market dominated by small players like TACODA and Revenue Science, even though the recent SmartAds launch by Yahoo! shows that the big boys want to play, too. During last week's conference call, Yahoo! noted that behavioral targeting is a core competency at the company. And even Google's AdWords takes into account what the search engine giant knows about a user.

Plenty is at stake. Advertisers are naturally willing to pay more for effective ad campaigns that reach eager recipients. Research specialist eMarketer projects that behavioral targets ads will grow from a $575 million market this year to a $3.8 billion market come 2011.

It's great to see AOL -- a company whose pedigree makes it likely to know its users better than most cyberspace titans -- make a move that will enhance its online stature. Rather than going to coda, it played it smart and went TACODA instead.

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Longtime Fool contributor Rick Munarriz realizes that behavioral targeting may seem a little too Big Brother for some. He does not own shares in any of the companies in this story. He is also a member of the Rule Breakers analytical team, seeking out the next great growth stock early in its defiance. The Fool has a disclosure policy.