After all this time, we've found a bug in the IWT code: it doesn't escape your subject text properly in the Reply Page. This produces a botched piece of layout as the browser sees a [textarea] tag too early...
In a previous job, we had to accomodate mailing addresses in China and other places in Asia (Japanese addresses are, for the most part, structured very differently to Western addresses.) Fortunately, we didn't have to do anything but re-display it in our own app.
Names were more fun, though. Unfortunately, you can't make quite the same assumptions about Firstnames and Lastnames with Asian names as you can with Western European names.
(A similar learning experience happened at a different place when we had to handle a wide variety of non-English text. I learnt a lot about UTF8 and migrating a database to it.)
Wade.