In a guest post on Andrew Sullivan’s blog last week, I described two new technologies that track and mine some of the transaction data created by commercial interactions. I indicated that this, rather than government spies, is driving most of the loss of privacy in the contemporary era.

Here is a great example of crossover: cops using your shopping patterns to find where you have moved even if you’ve changed your identity and live on all cash. I’ve worked a lot with these datasets, and it wouldn’t be quite as simple as the author indicates, but this is very doable.

On the other hand, it’s always amusing how simple attacks with $20 of equipment that use physical mechanisms – demonstrating the dangers of viewing technology only at an abstract level is dangerous – can overcome massive security systems. Individuals can sometimes beat Big Brother.