Google Latitude. It's a privacy nut's worst nightmare, but there are apparently immense privacy settings and safeguards.
It will place your friends' near exact locations on Google Maps (so parents can find kids, etc.) - using cell phone triangulation. Crazy!
http://googleblog.blogspot.com/2009/02/see-where-your-friends-are-with-google.html
Obviously, it's an opt-in service. And it actually sounds pretty cool - if you don't mind your friends knowing exactly where the world you are 24/7 (though you have to specifically allow that).
It will place your friends' near exact locations on Google Maps (so parents can find kids, etc.) - using cell phone triangulation. Crazy!
http://googleblog.blogspot.com/2009/02/see-where-your-friends-are-with-google.html
Obviously, it's an opt-in service. And it actually sounds pretty cool - if you don't mind your friends knowing exactly where the world you are 24/7 (though you have to specifically allow that).