A Google map appears in the bottom of the slide pinned to your location.
There are a few examples in the HTML5 presentation that don’t work correctly. On a Mac, Firefox 3.6.3 is the only one I could get to work with Geolocation, and even that gave me a location nearly 50 miles away.
Geolocation has a ways to go, if only (I think) because browser vendors are trying to figure the proper privacy protocol.