Regarding the accuracy of the map, here's how it works. A data packet that is sent from the map's server to your computer (like when your browser loads up the map image, for example) travels along a chain of servers - a route. This route can be discovered by either end, and the stops on this route (the servers passing along the data request) often have known geographical locations. The closest stop to your end of the route is taken as representative of your location. This is why it's not entirely accurate. However, I believe that the margin of error will not pass beyond the borders of a country (due to various factors).
