Most of your users are based in the US because those not in the US can't get in to use your service. =)
(Speaking of my websites, we've actually done the i18n necessary to make it usable from anywhere, but only after we knew we had that international demand.)
The first moment the craziness of i18n that I experienced was almost 10 years ago, building software for Koreans (I think, not sure, was a long time ago) and after the UI team demoed the product, one of the partners who was pushing this for the Asian market remarked they had to remove the red. Apparently, red is a taboo color or something over in that region.