In internet slang, a troll is a person who starts Flame wars or upsets people on the Internet by posting inflammatory and digressive, extraneous, or off-topic messages in an online community (such as a newsgroup, forum, chat room, or blog) with the intent of provoking readers into displaying emotional responses and normalizing tangential discussion, either for the troll's amusement or a specific gain.
Both the noun and the verb forms of "troll" are associated with Internet discourse. However, the word has also been used more widely. Media attention in recent years has equated trolling with online harassment. For example, the mass media have used "troll" to mean "a person who defaces Internet tribute sites with the aim of causing grief to families". In addition, depictions of trolling have been included in popular fictional works, such as the HBO television program The Newsroom, in which a main character encounters harassing persons online and tries to infiltrate their circles by posting negative sexual comments.
Trolls can be costly in several ways. A troll can disrupt the discussion on a newsgroup or online forum, disseminate bad advice, and damage the feeling of trust in the online community. Furthermore, in a group that has become sensitized to trolling – where the rate of deception is high – many honestly naïve questions may be quickly rejected as trolling. This can be quite off-putting to the new user who upon venturing a first posting is immediately bombarded with angry accusations. Even if the accusation is unfounded, being branded a troll may be damaging to one's online reputation