Actually guilds -must- have RP reasons for being, otherwise they\'re flat-out rejected by most of the community ;) All of the guilds listed within the Guild Forum are RP guilds, and so are many that are purely in-game guilds.
While RP itself isn\'t strictly enforced within the game (yet?), I would like to say that it is strictly encouraged - all Out-Of-Character text should go in parantheses or brackets, and prolonged OOC discussions in public channels are a no-no. The goal is to create as believable an atmosphere as possible :)