Convictions for internet abuse have more than doubled in the space of five years alongside the enormous growth in popularity of social media sites.
Official figures show the number of people found guilty under section 127 of the Communications Act 2003 has grown each year from 498 in 2007 to 1,286 in 2011.
The law has been responsible for some of the most controversial headlines of 2012, from the homophobic tweets sent to Olympic diver Tom Daley, to the "Twitter Joke Trial".
He was found guilty in 2010 of sending a "message of a menacing character" for tweeting: "Crap! Robin Hood Airport is closed. You've got a week and a bit to get your shit together, otherwise I'm blowing the airport sky high!"
The law prohibits "sending or causing sending of grossly offensive/indecent/obscene/menacing or false message/matter by electronic communications network".
Labour MP Andrew Gwynne, who requested the figures in a parliamentary question, called for internet guidelines to curb internet harassment.
"Given the massive growth in the internet and other media like Twitter and Facebook, it is hardly surprising that there has been such an increase in harassment convictions over the electronic media," he said.
"It is important that there are guidelines governing the internet to ensure it isn't used to harass people."
But freedom of speech campaigners have criticised section 127, claiming that it is being overused by the police and prosecutors.
Many of the prosecutions and arrests have included the targeting of public figures and celebrities on social networks, and jokes made at the expense of victims of crime.
In October, a Lancashire man Matthew Woods was sentenced to 12 weeks in a young offender’s institute for making jokes about missing Welsh schoolgirl April Jones on his Facebook page.
In September, a man who made a Facebook tribute to Dale Cregan, suspected of murdering two Manchester police officers, suggesting he receive an OBE, was arrested under the Act.
And in March law student Joshua Cryer bombarded the football commentator Stan Collymore with racist tweets, and was sentenced to two years' community service and ordered to pay £150 legal costs.