AR browsers include those like wikitude, Layar etc that are available for Iphone and Android smartphones .
When you point your camera to a landmark they automatically overlay previously available information for a location over it (e.g. name of a restaurant over its door)
If the accuracy of GPS as states by some is ~ 10 m , how can this be done accurately ?
I mean if they track the location of your phone to display geographically accurate information , a difference of even 2-3 m can cause havoc.