Plenty of people will tell you that you don't really care, or shouldn't care, or need not bother caring, because the protected space of our personal lives disappeared in the olden days of the 1990s. These people do not have your interests at heart. They depend on the hope that you'll forget about privacy the same way you forget about that camera in the elevator. Oracle's Larry Ellison ( "the privacy you're concerned about is largely an illusion") is the guy who wants to supply software for a national ID system. Facebook's Marc Zuckerberg (there's no more "social norm" of privacy) owns a multibillion dollar business based on extracting your intimate details. (Here's an illuminating graphic that shows how Facebook does it.) Google's Eric Schmidt, whose company depends on promiscuous data collection, endorsed the FBI equation of secrecy with wrongdoing: "If you have something that you don't want anyone to know, maybe you shouldn't be doing it in the first place."
Everyone has something to hide. Privacy is relational. It depends on the audience. You don't want your employer to know you're job hunting. You don't spill all about your love life to your mom or friends. You don't tell trade secrets to your rivals. We don't expose ourselves indiscriminately, and we care enough about exposure to lie as a matter of course. Among upstanding citizens, researchers have consistently found that lying is "an everyday social interaction" (twice a day among college students, once a day in the Real World). Remember the disasters that befell Jim Carrey in that movie plot that left him magically unable to fib for even one day? Comprehensive transparency is a nightmare.
Self-protection is a powerful instinct -- we try to safeguard our families, reputations and careers -- but instinct alone won't protect you in cyberspace. Digital security is full of trade-offs, a shifting balance of risk and cost and convenience. Your choices will depend on the stakes and threat as you see them.