Via the BBC comes a link to a fantastic article in the Chicago Tribune about how you can find CIA agents and installations by searching the Internet.
This is actually not a new problem – the fact that by searching for behaviors in many databases at the same time, you can uncover patterns that point to people. The term when I heard if first – in the early 80s – was Rasterfandung, which is German and means something like "sieve finding". The story was that the police in one city in Germany was looking for a terrorist, and used a number of computerized registers to focus in on people of the right age group who had recently rented an apartment, hired a car, etc. The police then charged one specific apartment and found the terrorists inside.
The problem, of course, is the perennial one of false positives – what if you are a fairly innocent person cleaning a hunting weapon when the police comes barging through the door? Anyway, the way to mitigate against this kind of searching is, as the corporate blogosphere is beginning to pick up, to flood the net with false positives. I wonder how the CIA (or anyone else) can do that?