Here's one for you from Bruce Schneier, the CTO of Counterpane Internet Security and the author of Beyond Fear: Thinking Sensibly About Security in an Uncertain World, published over at Wired. From the middle of the essay:
Cardinal Richelieu understood the value of surveillance when he famously said, "If one would give me six lines written by the hand of the most honest man, I would find something in them to have him hanged." Watch someone long enough, and you'll find something to arrest -- or just blackmail -- with. Privacy is important because without it, surveillance information will be abused: to peep, to sell to marketers and to spy on political enemies -- whoever they happen to be at the time.Surf over for the full read.
Privacy protects us from abuses by those in power, even if we're doing nothing wrong at the time of surveillance.
We do nothing wrong when we make love or go to the bathroom. We are not deliberately hiding anything when we seek out private places for reflection or conversation. We keep private journals, sing in the privacy of the shower, and write letters to secret lovers and then burn them. Privacy is a basic human need.
A future in which privacy would face constant assault was so alien to the framers of the Constitution that it never occurred to them to call out privacy as an explicit right. Privacy was inherent to the nobility of their being and their cause. Of course being watched in your own home was unreasonable. Watching at all was an act so unseemly as to be inconceivable among gentlemen in their day. You watched convicted criminals, not free citizens. You ruled your own home. It's intrinsic to the concept of liberty.
For if we are observed in all matters, we are constantly under threat of correction, judgment, criticism, even plagiarism of our own uniqueness. We become children, fettered under watchful eyes, constantly fearful that -- either now or in the uncertain future -- patterns we leave behind will be brought back to implicate us, by whatever authority has now become focused upon our once-private and innocent acts. We lose our individuality, because everything we do is observable and recordable.