GPS isn’t the only use for location data. There are millions of San Francisco WiFi hotspots in homes and in businesses. They don’t move very often so Skyhook drives around creating a massive database of locations to turn the hotspots into an accurate navigation tool (it powers location in Google Maps on smartphones). It’s not as accurate as GPS, but it’ll pinpoint your location within 20 to 30 yards, which is enough to find you on a street. The next step will be what Skyhook calls XPS, a system that uses cell location and GPS along with WiFi locations to find you quickly, helping phones and PNDs zero in on your location.