pnichols: and you have to trust Google to not retain that data without your knowledge too. (Knowing full well that Google is one of the worst offenders to consumer privacy.)
Do they? IDK, but several large companies have been in the news in the last year over retaining and selling customer data. Their typical response is "there is no customer specific identifying info in what we sell". Which in many cases has been shown to be a lie.
Remember folks, they track you by your computer's MAC address too. Change it regularly.
And now I will stop before someone labels me a tinfoil hat nut for pointing out verifiable facts.