A man gets done for contempt after making a video, or was it trying to make a video, whatever, about an ongoing court case. If such publicity prejudices juries, do social media posts have the same effect? I think if I were to look up the name of someone on trial, I'd be at least as likely to find their facebook page as a youtube vid. It seems to me that Tommy Robinson's conviction has set a precedent which will enable defendants' lawyers to move for mistrial on the grounds of prejudicial internet publicity, because there's no way the court can track down and hold in contempt everyone who attacks a defendant on their facebook. Which in turn means defendants can improve their chances simply by getting their supporters to act as agents provocateurs and slag them off online.
The only way to prevent juries being potentially influenced is to have a blanket ban on the names of defendants being released pre-trial. There don't seem to be any clear rules on this. Sometimes we get full details of people accused of crimes, sometimes we just get "A 32 year old man has been charged" or whatever. Before the internet, paddy wagons arriving at courts were traditionally mobbed by hysterical women presuming the guilt of anyone charged with a sex crime or a crime against a child because they read the local newspaper. The internet has given an unlimited number of such instant judges a massively bigger and more accessible platform.
The judicial system is ancient and couldn't have anticipated this form of broadcast prejudice, but it can't ignore it now that it's here. It has to adapt because it is now too easy for any number of people ignorant of anything but the headline to potentially undermine a case.