In another strong technology move for Nielsen, it has been announced that is partnering with the ratings company so companies who purchase inventory from the Google TV Ads program can find out how many people actually watch them. as a result of the partnership, Google will have access to demographic data from Nielsen's set-top boxes, so that ad buyers can actually see what they're getting for their money.
Google, since the advent of it's CPC search ads, has turned advertising into more and more of a science, where its advertising based on the numbers, instead of the art form some consider broadcast advertising to be (spend some money and hope it works). In terms of Google's broadcast advertising options, previous to the Nielsen deal, the general AdSense userbase must have considered it a unsavory investment of advertising dollars.
The partnership between Google and Nielsen is to be multi-year and strategic in nature. They plan to look at other ways for the two groups to work together and "measure online and other media." They didn't go into details, but with Nielsen's new-found interest in all things online (like their partnership with Wizzard) and Google's insatiable desire to index everything, it looks to me like the two will be going steady for quite some time.