What to do about people making threats and threatening comments?

This one isn't so bad but brought up the question:

http://www.reddit.com/r/MensRights/comments/e0q80/friend_of_mine_was_falsely_charged_with_sexual/c14dxz3

I feel very uncomfortable about the post at the end encouraging people to come to him to "'discuss' it". Especially since I banned him (and his follow up account) and it clearly shows him that I am the one who banned him (not a good feature, in my opinion - the mod list is already available and that should be enough).

While he seems to be all talk right now, I want to know what others suggest about people who may get more threatening and personal with their threats.