Wired investigated how much some of the largest U.S. internet service providers spy on you:
Wired News, with help from some readers, attempted to get real answers from the largest United States-based ISPs about what information they gather on their customers' use of the internet, and how long they retain records like IP addresses, e-mail and real-time browsing activity. Most importantly, we asked what they require from law-enforcement agencies before coughing up the data, and whether they sell your data to marketers.
Only four of the eight largest ISPs responded to the 10-question survey, despite being contacted repeatedly over the course of two months. Some ISPs wouldn't talk to us, but gave answers to customers responding to a call for reader help on Wired's Threat Level blog..