Originally posted here by JonnyFrond
Well hey Phobia, we are streets ahead of you then, because we have rewarding store cards that let them know what food we buy, and we have a thing in London called an oystercard which is a magnetic proximity card which you hover over a terminal on buses and trains which will let them know which bus or train you got on to go home, and also let them know with the aid of your credit card whether you stopped off for a pint on the way home.

We have the reward cards and so on in the US as well. While the government prolly has minimal involvement in this, it would be no different for them to ask for this information on your purchasing habits than it is for them to request your library records or the google web logs.