Yes, I got you, I was just pointing out to you that if in-real-life stores are capable of following you out of the store using their CCTV systems there is absolutely no reason to assume that you can't use a website's analytics suite to couple that with other databases at your disposal.

The major reason why companies will self host analytics services is not because they are trying to protect the privacy of their visitors, it is because they don't want to give out business critical information to third parties.