There’s a book excerpt at the Chronicle of Higher Education that takes apart the argument that privacy isn’t necessary if you have nothing to hide.
[S]uppose government officials learn that a person has bought a number of books on how to manufacture methamphetamine. That information makes them suspect that he’s building a meth lab. What is missing from the records is the full story: The person is writing a novel about a character who makes meth. When he bought the books, he didn’t consider how suspicious the purchase might appear to government officials, and his records didn’t reveal the reason for the purchases. Should he have to worry about government scrutiny of all his purchases and actions? Should he have to be concerned that he’ll wind up on a suspicious-persons list? Even if he isn’t doing anything wrong, he may want to keep his records away from government officials who might make faulty inferences from them. He might not want to have to worry about how everything he does will be perceived by officials nervously monitoring for criminal activity. He might not want to have a computer flag him as suspicious because he has an unusual pattern of behavior.
The excerpt points to data aggregation by governments as a bigger current threat to privacy than the surveillance used to collect that data. Read the whole thing here.