Google's collection of Web properties somtimes seem unconnected and disorganized. But there's a common thread between Print Ads, Audio Ads, TV Ads, Checkout, YouTube, Postini and DoubleClick. Can you guess what it is?

Google's top executives desperately want to convince Wall Street that it's on the verge of cracking the $70 billion television-advertising business — automating it, rationalizing it, and ruling it, as it has done with the considerably smaller search-advertising market. They've even hired an NBC executive, Michael Steib, to sell broadcasters on the idea. The only problem: It will never work, as Google's own documentation shows. Google's triumph in search is a product of its skillful use of data. By analyzing what Web searchers click on and what advertisers say they'll pay, it's able to continuously refine the ads it displays to yield the most clicks for advertisers and the most profits for itself.