We are all excited about what we can do on cell phones (and especially the iphone) making use of location information. It’s surprising though how little use is made at web sites today of the already available geo information. There are many different vendors (MaxMind, Quova, Ip2Location, Geobytes, …) that provide databases of IP address blocks either for download or as a web service. It’s true that these are not 100% accurate, but for many applications they could provide significant value for...