I think the like and dislike button only serve to represent multiple people backing or condemning a specific point of view. Unlike Reddit, forums take a lot of vertical space (especially with signatures), making a very long read. I personally really don't like having a like or dislike button, but it would simplify communication on the forums if I could just like someone's comment instead of making my own to show that I agree with them. I would only add likes, as dislikes can create a war where two sides try to dislike each other into ground.