Apple and Google aim to track users’ phones with GPS and W-Fi trangulation.
Google’s new service, Latitude, lets people spy on each other, by tracking their target’ GPS receivers. Now Apple is rumored to be adding Wi-Fi triangulation to the Mac OS.
OS X Snow Leopard to get WiFi triangulation, more multitouch control? – SlashGear
Mac OS X 10.6 Snow Leopard could introduce WiFi triangulation, used to estimate geographical location, in a crossover of the technology from the iPhone to the MacBook range. The system- which is part of the CoreLocation framework in the iPhone SDK – will presumably be used to give general location information to navigation software such as Google Maps, as the first-generation iPhone did to compensate for its lack of true GPS.

I pitched my cell phone a while ago. Not just for this reason (though this was definitely on the list), but just to revive that antiquated notion of what we used to call privacy and personal space.
This is the most amazing thing to me, more amazing than Facebook, these websites (Google Latitude isn’t the first) that people use to voluntarily upload their GPS data.. so you can follow them around.
Wi-Fi triangulation is pretty damn accurate, too. There are just too many exciting possibilities (for the watchers) once we have ubiquitous wireless networking in place.