Just confirming what I already knew.
No need to fight against machine-readable passports with RFIDs (c.f. #biometrischer pass). Your regular cell phone (that’s without any fancy GPS functions) already provides all the data needed to track you wherever you go.
c.f. this Namics presentation on Internet trends.
Add some pattern matching with some other online tools and voilà you’re identified.
Some links mentioned in the presentation:
Wikipedia on Reality Mining:
Reality Mining is the collection and analysis of machine-sensed environmental data pertaining to human social behavior, with the goal of identifying predictable patterns of behavior.