I've been traveling around the world for almost three years now. Without a doubt, nothing is more frustrating than trying to access Google, say in Argentina for example, and being presented with a Spanish website. I don't have exact numbers, but I'd say 80% of companies use some form of GeoIP (geo-location using the IP address as a means to determine where you are) to decide which language to serve you. The problem of course is that even though I am currently in Portugal, I don't speak Portuguese! So using GeoIP to determine where someone lives is fine, but it should never be used as a method ...