Google My Location in Google Maps is able to find your approximate position with good accuracy. Although it's clear that it makes use of GeoIP mapping, they need a more accurate strategy to pinpoint your location.
It is claimed that it uses the WiFi access point information to pinpoint your location. However, I don't understand the strategy behind this.
Did they map the WiFi access points around the world with the Google car? Or do some access points provide information about their coordinates (obtained via GPS)?