SAN FRANCISCO - Google Inc. and Clear Channel Communications Inc. announced a long-term agreement Sunday that will allow the Internet search leader to place advertising for its online customers on more than 675 Clear Channel radio stations.

"This radio partnership with Clear Channel is a pretty big statement that Google is in the radio industry to stay and have a big impact," said Drew Hilles, Google Audio's national sales director.

The agreement will give Google advertisers that had not relied on radio direct access to Clear Channel's national distribution system through an easy-to-use interface, Hilles said.

It will also allow those customers to target their campaigns, reaching particular audiences in targeted locations at specific times, and to get quick feedback about their campaigns, he said.

"This is a true win-win," John Hogan, chief executive of Clear Channel's radio division, said in a statement. "Clear Channel Radio gets access to an entirely new group of advertisers within a new and complementary sales channel, and Google adds another option for its existing customers."

Simply put, Google is opening up online radio ad placement to the masses. The current method for buying radio ads entails dealing either with a media buying agency, directly with the radio network, or directly with individual stations' sales staffs... there are a lot of sales commissions handed out in the process.

Generally, a radio ad campaign requires volume commitment to be effective... it's mass media akin to television, it's cheaper and is best used for brand promotion. Radio ad sales professionals will espouse that "as an auditory medium, radio will put your name into the listener's brain as effectively as someone giving them a personal referral to you".

It's that kind of implied referral-based branding that has made mortgage brokers avid radio advertisers. The ease of online radio ad placement offered by Google should attract local real estate brokerages and agents.

Producing and placing radio ads requires specific knowledge of production, ad copy, voiceover and comparative analysis of radio audience profiles. Google conceptually makes the process more transparent by providing its auction-based purchase model to "testing" radio ad campaigns. There will be a cottage industry forming around consumer radio production advice.

Google seems to have announced its Clear Channel agreement on Sunday to hedge any Wall Street concerns on the high price of its Double Click acquisition announcement Friday. They are saying we're proving we can propagate the Google Advertising OS so endorse our big deal, analysts. So far Google stock is UP.