At the moment we have a report function, for gold spammers, botters and all round nasty people.
What about the people that go out of their way to help their fellow gamers? Whether it be via in depth chats to help someone who has been asking questions on /map or the people that show others that are struggling to find that way up to the vista?
I realise that this would of course be exploited at the first opportunity, however if the reward were small enough (a 10 karma pt boost) and only available once per character per day or some such. I think it could be a good system to reward those gems of people that help others all the time.