Mobility or Tracking?

NSA granted Net location-tracking patent:

'The National Security Agency has obtained a patent on a method of figuring out an Internet user's geographic location.

Patent 6,947,978 describes a way to discover someone's physical location by comparing it to a "map" of Internet addresses with known locations.

The NSA's patent relies on measuring the latency, meaning the time lag between computers exchanging data, of "numerous" locations on the Internet and building a "network latency topology map." Then, at least in theory, the Internet address to be identified can be looked up on the map by measuring how long it takes known computers to connect to the unknown one.'

Read more at C.Net