More to the point, when Google sought approval to buy DoubleClick, they testified before congress that they would not merge information gleaned from your use of Google services with your advertising profile.
If their CEO's congressional testimony on this point isn't considered binding at Google, verbiage on their website certainly isn't.
> To assuage concerns, Google told Congress and the FTC that it would not combine the user data it got from assets in search, e-mail, or GPS maps with information from DoubleClick about which consumers visited which publications. And so, the acquisition was greenlighted. Ten years later, though, Google did not hesitate to break its promise.
