Although the spokesman declined to disclose additional details, rumors swirled Tuesday that the company was planning a major expansion into radio sales by broadening an alliance with Clear Channel Radio.

Google in April forged a deal with Clear Channel Radio to introduce AdWords paid search ads to more than 1,100 of the radio titan's Web sites--but that deal didn't include a broadcast element. Now reports are circulating that Google may buy $1 billion of ad inventory from Clear Channel to jumpstart the Audio Ads service, or may buy a stake in the company itself in cooperation with private equity firms. Clear Channel's management has been weighing a leveraged buyout that would take the publicly held company private.

Separately from a possible Clear Channel deal, the rollout of Audio Ads will complete Google's move into radio ad sales--an effort that began in January with its purchase of dMarc, a firm specializing in the automated sale and placement of radio ads through an online interface.

Google began selling radio ads through an online auction system using dMarc's technology this summer, when it launched an experimental sales campaign in the Detroit area. However, sales to date have only been targeted by market, demographic target, or station--the traditional currencies of radio sales. With the rollout of Audio Ads later this year, Google will offer customers the ability to target ads by their context in broadcast airplay, using Google's Ad Words online interface.

With the new Audio Ads, Google probably intends to introduce metrics similar to online click measurements to radio advertising. In a February interview with MediaDailyNews, Patrick Keane, Google's director of advertising strategy, hinted that Google might try to drive listeners back to the online realm and measure them there: "The smart advertisers have been coming up with linked campaigns for a while. They're no longer conceiving of advertising campaigns that are limited to the various silos--just print, just radio, or just Internet, and so on."

For example, Keane said marketers might potentially include a unique URL in text ads, allowing advertisers to measure by site visits the number of visitors who interacted with the text ad. He suggested that advertisers could cast an even wider net by including an old direct response technique--the unique 1-800 number--in print campaigns and radio advertising.

Google has also stepped up its role in print advertising sales, and plans to begin offering space in major newspapers to its online search advertisers. The search giant is readying an effort to sell ads in 50 major newspapers, including papers published by Gannett, the Tribune Company, The New York Times Company, the Washington Post Company, and Hearst. Google reportedly will begin testing the system with 100 advertisers later this month.

Google will begin taking a cut of the revenue next year, after the initial test phase; the search company usually garners about 20% of the ad revenue, according to The New York Times. Among the marketers testing the program is Denver-based online retailer eBags.com.

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