Social media users who knowingly break court orders by posting prohibited information online, such as the identities of James Bulger's killers, can "easily" be prosecuted, a legal expert has warned.
Joshua Rozenberg explained: "If you can show that somebody knew that there was a court order in force, as this man last week, who was very nearly sent to prison - in the end he got a suspended sentence and a hefty financial penalty.
"But if you know that there is a order saying you can't publish a picture of Jon Venables, then it is obviously more easy for the Attorney General to prosecute you."
Careless tweets have landed a host of celebrities in trouble in the past with comedian Alan Davies, Sir Bob Geldof's daughter Peaches and Sally Bercow all finding themselves in legal difficulties due to their online posts.
Social media users have also found themselves in contempt of a court - nine people admitted naming the woman raped by footballer Ched Evans on Facebook and Twitter.
They were all told to pay the victim £624 each.
The Attorney General said he was publishing legal guidance notes previously only issued to the media to "help stop people from inadvertently breaking the law."
Dominic Grieve QC said: "Blogs and social media sites like Twitter and Facebook mean that individuals can now reach thousands of people with a single tweet or post. This is an exciting prospect, but it can pose certain challenges to the criminal justice system.
"In days gone by, it was only the mainstream media that had the opportunity to bring information relating to a court case to such a large group of people that it could put a court case at risk.
"That is no longer the case and is why I have decided to publish the advisories that I have previously only issued to the media.
"This is not about telling people what they can or cannot talk about on social media - quite the opposite in fact, it's designed to help facilitate commentary in a lawful way.
"I hope that by making this information available to the public at large, we can help stop people from inadvertently breaking the law, and make sure that cases are tried on the evidence, not what people have found online."
The Attorney General will publish legal guidance notes online to help prevent Facebook and Twitter users from breaking the law by inappropriately commenting on court cases.
The Government's chief legal adviser Dominic Grieve QC will in future issue previously unpublished advisory notes in a bid to stop social media users from committing a contempt of court.
He said the move was designed to make sure that fair trials take place and will apply to court cases in England, Wales and Northern Ireland.
The advisories, which have previously only been issued to the media, are being put into the public domain so people avoid legal pitfalls by commenting on court cases in a potentially prejudicial manner.
The advisories will be published on the Attorney General's Office (AGO) section of the gov.uk website and also through the AGO's Twitter feed - @AGO_UK.
A Muslim woman accused of witness intimidation has been told to remove her burka by a judge before entering a plea in his court in case she was an imposter.
The Judicial Office said the 21-year-old from east London had initially refused to remove her full veil and reveal her face at Blackfriars Crown Court.
But judge Peter Murphy said the court's pursuit of open justice trumped her religious beliefs.
He also turned down a request from the woman's barrister for a female member of the police or prison staff to confirm her identity from arrest pictures before she entered the court.
The case was adjourned until Sept 12, when he may hear legal argument about the issue.
Justice Secretary Kenneth Clarke said: "The Government wants a libel regime for the internet that makes it possible for people to protect their reputations effectively but also ensures that information online can't be easily censored by casual threats of litigation against website operators.
"It will be very important to ensure that these measures do not inadvertently expose genuine whistleblowers, and we are committed to getting the detail right to minimise this risk."
Websites will be forced to name people that send defamatory messages online under new Government plans.
Websites will be given greater protection from being sued if they help to identify internet trolls, under new Government plans.
Reforms of the libel laws will see a duty placed on internet service providers to try to identify those posting defamatory messages without victims needing to resort to costly legal action.
The Defamation Bill, which will be debated in the Commons today, will also see would-be claimants having to show they have suffered serious harm to their reputations, or are likely to do so, before they can take a defamation case forward.