Google bought dMarc Broadcasting last January and many are speculating on google ads on radio. It is on beta testing right now in the US.

Google Audio Ads brings efficiency, accountability, and enhanced ROI to radio advertising by providing advertisers with an online interface for creating and launching radio campaigns. You'll be able to target your customers by location, station type, day of the week, and time of day. After the radio ads are run, you will be able to view online reports that tell you exactly when your ad played.

Google has been partnering with terrestrial and satellite radio stations all across the US. This would enable advertisers to target their ads to a specific area.

The problem with audio ads is that it isn't trackable. Unlike internet ads, each click can be monitored and measured. Advertisers would have to use a unique URL for their audio ads in order for them to track how many users end up to their site from the audio ads.

The nice thing about google audio ads is that there is no click fraud. Apart from that, it brings radio advertising to a broad spectrum of publishers. It would be easy for anyone now to buy radio ad spots.