'Bury This Post'
 

Anyone who has used the comment system on digg.com and similar sites will notice that some responses are minimised/greyed out, that is usually because they are spammy or garbage and other users have 'buried' them.

I'd like to see this idea translated to forums, if someone makes a crap post in a thread or spams, it could serve to allow the community to almost 'moderate' itself to some extent, say 4 or 5 people in a thread clicked a 'bury this' button, then that post is soft-deleted (but retains a 'click to view' link for all users to see if they want?)

I hope I've got the idea across well here, I think this would be a really useful feature. To sum it up, you'd have a button on the postbit and if enough users clicked it, a post would be in essence removed until a moderator came to un-bury it or something.