Following Google Inc.'s (NASDAQ:GOOG) announcement that it would make a misguided move into the newspaper ad space, late news comes that the search giant may buy $1 billion in radio inventory.

The clear winner in this would be radio giant Clear Channel Communications, Inc. (NYSE:CCU). If Google buys such a large block of time from the radio chain, Clear Channel's flagging fortunes in an ailing industry could be reversed, at least temporarily. Four years ago, Clear Channel's stock traded at $53. It now changes hands around $35, having made a move up from $28 on buy-out rumors.

Still, it is by no means certain that Google's second foray into traditional media this week will work. The system Google is offering will allow its advertising customers to use the company's AdSense system to sign up for radio advertising by picking radio advertising the way it would AdWords. Google argues that this is an efficient means for buying time on stations.

But is it? Radio is targeted by region first, and then by demographic segment and programming type. Buying radio is not rocket science. It is actually a simple and effective means for targeting people, especially during "drive time" rush hour, from 6 a.m. to 10 a.m. and then again in the late afternoon.

Radio can only be as efficient as the size of its audience. Satellite radio and in-car iPod have cut into this audience and that is likely to continue.

Like newspapers, buying advertising in a medium with a falling audience may not be attractive, whether the ads are bought through Google or directly from the source.

Douglas McIntyre is a partner at 24/7 Wall St.