Answer: Internet 'trolling' is the anti-social act of causing of interpersonal conflict and shock-value controversy online. Named for the wicked troll creatures of children's tales, trolling is purposely sowing hatred, bigotry, racism, misogyny, or just simple bickering between others. Trolls themselves are emotionally-immature users who thrive in any environment where they are allowed to make public comments, like blog sites, news sites, discussion forums, and game chat.

http://netforbeginners.about.com/od/netiquetteonlineculture/f/What-Is-Trolling.htm