So you use your "club card" to check out at the supermarket.
The clerk thanks you by name, and you get a coupon for an item you might like, based on your past purchases.
The store knows some of your habits. Do the things that company knows about you end up in the hands of anybody else?
That's one of the key questions of our time, and one of many considered by Heidi Boghosian, Executive Director of the National Lawyers Guild. Her book on the prevalence of surveillance in our society is Spying on Democracy: Government Surveillance, Corporate Power, and Public Resistance.