We've seen a few stories over the years about jurors tweeting or otherwise discussing trials via social media. Obviously, the courts don't like that, as they usually have bans on discussing cases publicly while they're ongoing. However, in a culture of sharing all sorts of things going on in one's life, it's difficult for some people to shut off. And, to be clear, I'm not entirely sure why it's so bad to talk about a case, in general. I can understand specific instances, based on what you're talking about, but an overall ban just seems unreasonable and unworkable. However, as the courts and governments deal with this issue, we're going to see more overreactions like the following.

California has now passed a law that will allow it to put people in jail for tweeting about a case as a juror. As that link explains, courts already have broad powers to penalize jurors who disobey court rules, including "improper" conduct or "interfering" with a trial. Thus, as Eric Johnson notes:

The current law seems to cover everything of substance. The only thing the new provision does that I can see is make it a jailable offense to use the internet in such a way that is neither improper nor interfering. I guess I don’t understand why we would want to jail jurors under such circumstances.

It seems like a typical grandstanding situation, where a politician feels the need to "do something" about an issue that's been reported on in the press, without realizing nothing needs to be done.