I was looking for it, I suppose in the wrong places.
To answer your question, I'd have to agree with what was already written by eric-hu, except to say that bad or inflammatory posts also create a lot of response (trolls, as it were). I know it's maybe tired or clunky, but I think a forum can have both entertaining and useful replies, and thus should have a voting mechanism to indicate which are which. Yes, interaction can play a role in how important they are, and to maybe help massage ranking, but I think people are happy with and familiar with a system of voting for content.
That said, a token "good post" should be able to stand for itself. I envision a system where the top posts (be they replies to other posts or posts in and of themselves) sit flat among each other, ranked by their usefulness or entertainment value.
I think a forum moderator's real value in this situation is not to mess with the community's decisiveness, but to resolve matters of content relevance (to keep a community focused).