I cant stand them. I dont mean the WoW race. The ones who spam trade channel and endlessly annoy people on forums.
Trade Channel Trolls- Trade channel is for goods and trade. Not for talking about anal (devastate) or Murlocs. It is annoying when you ask for a service in trade chat and it gets covered in 3 seconds by people spamming retarded random crap.
Forum Trolls- The ones who hand around on the forums for no other reason to make fun of someones gear/gems/enchants or just to put them down in general. For example, there is a mage on my realm forum that hops into most threads with a "lol INT gems are for noobs" or something to that effect. Is it really neccessary to be a troll all the time.
Dont feed the troll and they will die.