If Twitter is the chirping chatterbox of the Internet, trolls are its dark underground denizens.
The collision of the two is driving a debate in Britain about the scale of online hatred and the limits of Internet free speech.
The furor erupted this week after several women went public about the sexually explicit and often luridly violent abuse they receive on Twitter from trolls — online bullies and provocateurs who send abusive or disruptive messages, often for their own amusement.
Many regard trolls as an annoyance to be ignored, but there are growing calls for action when their abuse crosses over into threats.
Police are investigating a threat of rape and murder made to Labour Party lawmaker Stella Creasy by a user with the Twitter name @killcreasynow. The crude and graphically violent tweet was one of many Creasy received after she tweeted in support of feminist campaigner Caroline Criado-Perez. Criado-Perez was sent a torrent of invective after she campaigned, successfully, for novelist Jane Austen to appear on a British banknote.
Two men have been arrested in connection with the Twitter threats, but have not been charged.
Such abuse is neither new nor confined to Britain. American writer Lindy West wrote earlier this year about receiving a slew of sexual threats after she appeared on a TV debate about rape jokes.
But the subject has received an unprecedented level of public exposure this week, sparking debates on British radio and television news programs and articles in national newspapers — even the tabloids. Creasy and Criado-Perez are among a growing group who have decided to face down the abusers, retweeting their messages in an attempt to "name and shame" the offenders, and reporting the most threatening messages to police.