A mechanic from Southampton used Facebook to try to incite a riot and urged others to attack the police and Muslims during the height of last summer's riots, a court has heard.
Mitchell Stancombe, 21, made three posts on a public page of the social networking site on August 9 starting with the words: "When are we going to start the Southampton riots then?"
When told to shut up by a friend, he replied: "LOL - do a few coppers in."
He then made another post urging an attack on "the Muslim revolt".
Christopher Stopa, prosecuting, told Southampton Crown Court that on the day the posts were made, there was widespread rioting across England in Birmingham, Manchester, Derby, London and Liverpool.
Stancombe, from Totton near Southampton, denies encouraging and assisting people to commit violent disorder under section 44 of the Serious Crime Act 2007.
Mr Stopa told the jury the posts should be seen in the context of the rioting across England.
"If you look at these three posts together, the only possible explanation is that he was trying to encourage other people to get involved in violent disorder," the barrister said.
Hampshire police had been monitoring sites like Facebook during the riots in an operation costing £500,000 and Stancombe was arrested.
He told officers the posts were an ill-advised joke and he did not intend to encourage anyone to riot.
But the prosecution allege Stancombe was serious and the posts could have incited others even though no disorder took place in Southampton.
Giving evidence, Stancombe said his posts on his own Facebook account had been "blown out of proportion" and were "stupid and immature".
He said he did not realise his page could be seen by anyone and he thought that only his friends could see it.
He said he now realised that others could search for his name and see the page but he told the jury only his friends would have searched for his name.
He also said he knew people had got into trouble for setting up a Facebook account inciting riots but he had not done that.
"I was trying to have a laugh with people on Facebook but it was immature," he told the jury.
The case is expected to last two days.