I'd never even heard of this practice, hellbanning, slowbanning. I gotta say, and this may not be popular sentiment, that I view using such tactics as dishonest. You got a problem with someone, deal with it head-on. Don't resort to passive-aggressiveness, and don't yield to the oh-so-human desire for revenge the delicious poison of helping someone get what you feel they have coming to them.
Deal with problem users directly and honestly. Warn them, temp-ban them if it doesn't work, permaban them if they force you to, but not without telling them why.
I'm not speaking without experience. I've been the moderator of political threads in the off-topic section of a college football board for about six years. We've had to deal with some crazies.
It turns out that if you ban a certain set of users they will react strongly, often causing many more problems. At Chesspark I was just amazed at the lengths people would go to to get revenge for some perceived wrong when they got reprimanded for violating community standards.
Making them think nothing happened but removing them from the rest of the site is extremely effective.
Blackholing IPs is a poor solution in practice, since many users can change IPs on a whim, and some ISPs run DHCP out of large subnets that may contain respectable users.
Deal with problem users directly and honestly. Warn them, temp-ban them if it doesn't work, permaban them if they force you to, but not without telling them why.
I'm not speaking without experience. I've been the moderator of political threads in the off-topic section of a college football board for about six years. We've had to deal with some crazies.