Worse yet are the trolls that prowl RC forums, Roy. I ran into a few that were the most intolerant rotten little fellers. They actually attacked my husband's site and attempted to shut it down via javascript attacks because they had a political disagreement with the husband's belief system. They attacked him, me, our integrity, everything.
A good thing to do for admins (and I had to do this more than once when I used to run Napoleonic forums) is IP log. If you get the IP of the troll, do a WHOIS search, then a DNS search to come up with the offending beastie's ISP, write their abuse department and be prepared to provide a good detailed log of the offense.
http://www.dnsstuff.com/ is the link I use to discover where the troll might be slinking around.
If your BBS system has the ability, you can then block either the block of IP addresses the person uses, or the single IP they seem to be assigned.
Back in the day of unassigned IPS, (aka you got a new one each time you logged on - usually with the dial up guys) this was harder. But now, with Cable, T-1 and the other broadband "online all the time" IP services, the IP is usually fixed, so a single block of the IP will result in negation of the troll, unless said troll is smart enough to do a cold-boot and reset of their IP. (Some are, some aren't.)
I hate em, really I do.
One must also put into consideration, however, that long absences followed by a flurry of posts might also mean something else - The work week is over, there's snow on the ground and we're snowed in... etc etc.
