On the "don't allow new users to post comments for, say, 8 hours": Don't forget lot of people create a first account just to do a first reply. I would have feel not welcome the first time I try to comment if this protocol was implemented. More than that, I'm not sure that your proposal will resolve the fake-account problem: if I love to be a jerk I will play with 2 accounts, your 8 hours delay will not block me.