location matters (being a GIS practioner you can bet i think it matters). i've researched and used several geoLocation services, some of which are listed here on i18ngurus (and some of those have since gone belly up). while most of these services accurately show i'm coming from bangkok (the infosplit service, though, pinpointed bangkok as being in northwestern china near the mongolian border) none can really compare with nigel wetters' inetaddress locator. its free, its fast and works a treat with coldfusion.
once you know where somebody's located you can serve them content based on their locale, price products in local currencies, price products based on geographical location (within Thailand, free, everybody else pays double ;-), target ads, analyze web traffic (ala farcry), etc.