RMT chat spam is less prevalent on JP servers. Although it exists, it's rare enough that I forget about them easily. You can sit in a low level main city and not see one for up to an hour depending on the server. You'll still see the standard event shouts like RP or hunts, and the occasional FC recruitment—but even those aren't as much as I see on NA. They seem to like advertising on the Community Finder and Twitter instead of in game. (I haven't looked at their Fellowship Finder though to see if they actually use it or if it's been abandoned and forgotten like on NA.)