If you are one of the many complacent people out there who think that data mining to target ads is OK, you really should think about what else could be done with that information, because once it's out there, corporations WILL sell it to whoever will pay for it. (Just to be clear, I am not accusing Target specifically of selling this information. But if Target can do it, any big company can, and if any big company can, one will, and pretty soon they all will.) People could do all sorts of things with a list of women who are pregnant. Just think how much fun an unethical information broker could have selling the list to people on both sides of the abortion debate. (Even scarier: correlate the list of women who were pregnant a year ago with the list of those who don't have infants today to form a list of women who got abortions. If I need to explain how that could go badly, I think I'm wasting my time.) But maybe you're not in the demographic likely to become pregnant. It's worth considering that if they can figure out that women are pregnant by analyzing their purchases, they could probably figure out a lot of other things. Like if they're having an affair, or they're gay, or what political party they favor. And people you would rather not know whatever it is you'd rather not know about you can go buy a list with your name on it.
The real point that I want to make in this post is that we face a fundamental societal problem. Given that this computer technology exists, the records are going to be there, and if there is a way to make money from it, the records will be mined and people will be identified. I'm not trying to say computers are evil and we should stop using them; to begin with, I don't believe it, but much more importantly, it isn't going to happen, and trying to say that it should is a stupid waste of energy. What I'm trying to get at is that we need to place fundamental limits, not on what information is stored, but on how it can be used. Personal information -- where we go, how we spend their money, and the like -- fundamentally belongs to us, not to the corporation that happens to collect it. We need to collectively assert that corporations don't have a right to make money off of our information without our explicit permission, and that if they do, the money they make from it is fundamentally stolen and we have a right to collect it.