Spotting and dealing with Trolls is an art not a science. The YT Mods/Admin do a GREAT job
. The registration/validation process here is a big help too. I Admin a large, controversial, no registration forum so I know allllll about Trolls. The best way to deal with the them is to report them to the Mods. Mods have history and IPs that give them a different perspective than users.
These are my favorite links about Trolls:
General Info:
Internet Trolls
Troll types:
Flame Warriors Home
General Forum etiquette - PGish:
How To Behave On An Internet Forum (Internet: Useful Tips)