What is a troll anyway? Could it be someone who answers on here with their rants about your Q & A's that?

aren't hidden because you have nothing to hide only to find out that their Q %26amp; a's are hidden. I'm not sure of the definition so please enlighten me.What is a troll anyway? Could it be someone who answers on here with their rants about your Q %26amp; A's that?
In the Fairy Tales, trolls were evil creatures who lived under bridges. Regular people were afraid to cross a bridge alone or at night. At Yahoo a troll is someone who does mean things. They follow every question you answer and then they vote No Best Answer ; so you can never be voted Best Answer. One guy went into a member's Q and A and ';reported as abuse'; 29 questions in 2 minutes. THe member had to respond to 29 violation notices.What is a troll anyway? Could it be someone who answers on here with their rants about your Q %26amp; A's that?
An Internet troll, or simply troll in Internet slang, is someone who posts controversial, inflammatory, irrelevant or off-topic messages in an online community, such as an online discussion forum or chat room, with the intention of provoking other users into an emotional response or to generally disrupt normal on-topic discussion.