Seeing a lot of people tend do either keep their ingame and forums personalities seperated or actually don't have a playing account anymore, I would like to see the option to be able to do private messaging. The forums are, for some people, a different world next to the game itself.

If you are afraid of spamming and/or insulting through PM, activate it only for people with x amount of tag points and above, allow forums mods to punish people by taking their pm rights away and/or put a 'report this message' button down.

The only downside, opposed to keeping the forums somewhat cleaner, would be that some discussions would be held in private, which makes the forums less active and interesting (but those two terms are often linked :])