AOL’s AIM Instant Messenger provides a one of its kind Location based plug-in with which you can post your location information for your AOL buddies to see and also find their location. The plug-in also integrates with SkyHooks Wireless Postioning system that can determine and display your location to your friends through a wireless WiFi router connected to your computer.

From the FAQs,

Using an interface to your wireless network card driver they can access the wireless signals in range and determine a distance to each of these signals using an RSS (receive signal strength) word on each of the signals. Having the location of at least three signals (mapped using trucks) and the range to those signals a triangulation based formula can determine your coordinates.

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