A Troll is a person who posts outrageous message to bait people to answer. A Forum Troll delights in sowing discord on the forums. A troll is someone who inspires flaming rhetoric, someone who is purposely provoking and pulling people into flaming discussion. Flaming discussions usually end with name calling and a flame wars.
Trolls see Internet communications services as convenient venues for their bizarre game. To them, other Internet users are not quite human but are a kind of digital abstraction. As a result, they feel no sorrow whatsoever for the junk they post, and the insults they inflict. Indeed, the greater the suffering they cause, the greater their 'achievement'. At the moment, the relative anonymity of the net allows trolls to flourish.
Trolls are utterly impervious to criticism. You cannot negotiate with them; you cannot cause them to feel shame or compassion; you cannot reason with them. They cannot be made to feel remorse. For some reason, trolls do not feel they are bound by the rules of courtesy or social responsibility.
Perhaps this sounds inconceivable. You may think, "Surely there is something I can write that will change them." But a true troll can not be changed by mere words.
Don't become a troll.