Government geeks can identify you with spy glasses/facial recognition, already.

[Leonidas]

http://www.economist.com/node/21524829

IF YOUR face and name are anywhere on the web, you may be recognised whenever you walk the streets—not just by cops but by any geek with a computer. That seems to be the conclusion from some new research on the limits of privacy.

For suspected miscreants, and people chasing them, face-recognition technology is old hat. Brazil, preparing for the soccer World Cup in 2014, is already trying out pairs of glasses with mini-cameras attached; policemen wearing them could snap images of faces, easy to compare with databases of criminals. More authoritarian states love such methods: photos are taken at checkpoints, and images checked against recent participants in protests.