Who cares if someone knows you bought a book at amazon, or a hard drive at newegg.
The state cares.
Using anylysis of what books you buy, they can analyse your psychological profile, how you behave, where you go every weekend, or if you are a disident/oppositionist.
Actually, I CAN DO IT EASILY if I have enough statistical data (I am a programmer).
If I can do it means not only they can do it,
but they are already doing it.
After they determine you are a "threat", they either make you a non-rejectable offer, or they simply come at night and you are never heard from again.
I live in a post-communist country, so i know how this works. At first, they eleminate the handful that oppose the strongest. Then the next, weaker opposition, and then level lower and so on. Before you know it, there is
nobody that opposes them (the only left are opportunist carcass and cowards) - and
boom, there ya go - totalitarian state.
Do you think that totalitarian regimes are made in one day ? No, it is a slow process, exactly as the one that is happening now.