If you live in Detroit, the ads you hear on your commute could be coming from Google, News.com reports. The Web-search giant has struck a deal to sell radio ads for Greater Media, which owns 19 radio stations across the country, and the ads are already airing in the Motor City. It's the first radio deal for Google since it bought dMarc Broadcasting, which runs an automated system for buying radio-advertising time, for $102 million in January.

If Google's radio efforts spread beyond Detroit, it will be the first time the company has succeeded at selling anything other than Web advertisements. An earlier attempt at brokering print ads failed miserably, notes Bill Wise on MediaPost. But radio may be better suited to Google's efforts: The online bidding it uses to sell advertising works well for markets with some element of scarcity, argues Wise, and radio, with its narrow drive-time windows for reaching large audiences, is well-suited for such auctions.