Believe it or not, there are some loosely defined laws about certain aspects of this which I found out in another online game that I ADMIN. If the game is available to minors and in that game a minor is exposed to sexually explicit language or bahaviour or more specifically, is the target of sexually explicit language or behaviour, it is considered sexual assult of a minor. A lot like being busted for speaking sexually to a minor in a chat room. I don't think this includes simple profanity. In any case, one of two things MAY happen, either the offender can be charged with legal action (I don't know of this ever happening) or the game itself can be shut down (I know of this happening one time). The laws are slowly becoming more and more specific about vulgarity and sexual language in publicly accesible forums like online multi-player games.
My personal opinion is that using vulgarity in game or on these message boards is really a sad statement about a person. I would even go as far as to include the fake vulgarity (FU, Fug, Fuggin', etc.) in the "grow up and get over yourself" catagory.
In the game that I ADMIN, we've totally outlawed vulgarity and fake vulgarity in all of it's forms. Using it gets you ousted forever. It's an easy way to insure that we maintain a healthy atmosphere for all ages and weed out the morons <g>.
-Lux