[jgh]

I thought they already were using all this information to figure out your location. Google Maps knows pretty much exactly where in my building I'm sitting at with my laptop (I live in a long building spanning a block and the dot is over my apartment). So maybe not all that information, but going from the idea of fingerprinting a location with WiFi networks to other kinds of radio signal information doesn't really seem like a huge leap in thinking (though perhaps the implementation is tougher)