A great article on privacy on Pogue's Posts in the New York Times Blog:

OK, I'm as interested in privacy as the next person. But if someone were interested in harvesting phone numbers, why would he go to the trouble of launching this elaborate phone-services company? Wouldn't it be infinitely more efficient just to pick up a tidy, complete, ready-to-harvest, pre-compiled list of phone numbers--a little thing called the *phone book*?"