I know it has been mentioned before and usually gets a response of "we are considering it" or some equivalent, but I really think that MMO-C would benefit from a forum rep system, likely with some limitations such as:
Only logged in users can up or down vote a post.
A user cannot up or down vote their own post.
A user cannot up or down vote the same post more than once.
A user cannot up or down vote the same user in quick succession (say within 15 minutes of last vote for/against that user)
A user must have a certain number of posts/certain rep level to vote up/down (possibly higher requirements for down voting)
Limitations are only an idea, and I borrowed most of them in some form from other forums, mostly the stack exchange sites and city-data.