Before you hit the "LOL That's what's rep for" post, hear me out.
I was browsing WoWhead earlier today, and It came to my attention that people can downrank unhelpful or flaming posts, and when a post reaches a curtain - mark, it is hidden. I thought to myself that it would be really nice to have on Mmowned. Being able to downrank posts that consist of nothing but useless flaming, and it can possibly stop trolling as well. Or, you could also make it that instead of it being hidden, it's deleted.
Now, The first flaw I would think of is abuse, but, that's why you make downranking posts only available to member status and above, or maybe just contributers and above. That way it's not misused. This can also stop all the useless exploits or reposts. A few people downrank it, and it gets deleted. Maybe set the deletion mark for -15 if it's only available to contributers, or 30 if it's set to members and above.
I have no clue if this is possible with this type of forum, I've seen it once or twice before on forums, but my memories fuzy. If it's not possible, flame on.