Wil Shipley wrote an article on application localization in which he explains tricks he uses to add support for as many languages as possible. He also emphasizes the purpose localizing too. You can make more money (plus you can tell friends that your an international man of mystery)! If you were selling an off the shelf product, wouldn’t you want to put that product on the shelves of as many stores as possible? Of course. It’s called distribution. Having experience with the App Store, I can tell you that your audience isn’t limited to the US, but the whole world. If you localize your application for everyone, you stand a change to widen your distribution and reach more customers. Here is a chart of the percentage revenue per region I’ve seen on the App Store.