Trying to silence social media will be like trying to herd cats, or to get everyone to vote for the Nazi party. The genie is out of the bottle. Social media now exists. It is a phenomenon of the "NOW". It is the modern day equivalent of what used to be said down the pub, over the garden fence, in the barber's chair, or behind the bike sheds at school.
The big difference is that everyone else on the same system can now see what you - and everybody else - just said.
And that can NEVER be shut up. They can pass all the laws they like, but they will not stop the effect. All they'll achieve is to make it even more enticing for those not already on Facebook or Twitter to get on there to see what all the fuss is about!
I think it should all be the other way around - the legal system should adapt to the fact that social media exists, and work with it.
For the 12 people on any given jury (interesting side thought - in these metricated days, why do we still have a dozen jurors or eggs?), they can only have been exposed to 12 lots of gossip, whether by social media, the MSM, or down the pub, over the garden fence, etc etc, before being selected for jury duty.
Personally, I really don't think that a jury, consisting of 12 members who have a tendency to keep each other in check and on track, will be unduly swayed by what they've already seen or heard. They are already instructed by judges to ignore some things that come up in court that are then subject to objection. They are also denied access to evidence that is deemed inadmissible for various legal technicalities by the judge.
I just think the legal system needs to get out of the dark ages in so many ways, and that it should be able to do so without compromising the administration of justice.
With regard to social media, the words, "horse", "stable door", "cat" and "bag" all spring to mind....