The government will now tell you which criminal investigations you shouldn't tweet about.
The government is desperate to avoid tweets or Facebook messages revealing too much information about criminal investigations and ruining trials.
The Attorney General currently attempts to control the spread of information by issuing warnings when they are fears that media coverage of an investigation could prejudice a trial – such as when former SAS sniper Danny Nightingale was court martialed and newspapers ran a campaign to have him exonerated.
Until now these warnings have only been issued to a small clique of traditional newspapers, radio stations and TV broadcasters. The recipients are not allowed to mention that they exist.
But the system has failed to keep up with the times. Now anyone can reach millions of people with a single tweet and it has been decided that it's safer to put the notices online – so everyone can know what they shouldn't tweet about.
This is a complete change in direction. And risks drawing the internet's attention to controversial cases.
Bristol teacher Christopher Jefferies was wrongly arrested in 2010 following the murder of his tenant Joanna Yeates.
Media coverage of the arrest was so biased that the Attorney General issued a notice warning that even if police wanted to bring charges, they may be unable to do so because the public would already be so prejudiced against Jefferies.
But as the local police told the Leveson inquiry, even they weren't told that such a notice had been issued.
The Attorney General typically issues five such warning notices a year – but a record ten have already been published during 2013. The danger is that making such notices public will actually draw the internet's attention to controversial cases.
The days of tweeting at leisure and not worrying about the law are over.
Sally Bercow, the wife of House of Commons Speaker John Bercow, had to pay Lord McAlpine £15,000 earlier this year after libelling him in a tweet.
Now the Attorney General is making warning notices public there will be fewer excuses for not abiding by the same rules that media outlets have to follow.
Which makes him more likely to punish people who break the rules by discussing the likely guilt of a suspect on Facebook or publishing information on Twitter that a court has decided should not be public.
...and as Peaches Geldof found out, contempt of court can still cause trouble on Twitter even when a case appears to be over.
Last week Geldof tweeted the names of the mothers of the babies involved in the Ian Watkins paedophilia case. This was in contempt of court because it indirectly identified the children who were rape victims.