More Google Radio

The New York Times has another piece on Google's offline advertising ambitions.

In particular, Google’s effort to sell radio ads, the oldest and most advanced of its major offline advertising plans, has run into several hurdles, including radio stations that are wary of losing control over the sale and pricing of ads.

The promise Google offers old-line media markets is that it can replicate the formula that has worked so well for it online. It is a formula that relies heavily on technology to allow advertisers to buy their own ads, have them appear on relevant pages across a vast network of Web sites, and then track the results.

The key phrase there is "then track the results". How do you programatically track the results of CPM based advertising?

I blogged this extensively a while back.