In the middle of the evidence-giving at the Leveson enquiry yesterday I saw a tweet posted by a quite prominent media figure. He's not a journalist, which may explain why he was re-tweeting an outrageous allegation about the people giving evidence, which was in turn allegedly tweeted by another prominent person.
Maybe the mood of righteous indignation had got to him. It took him only a few minutes to post another tweet pointing out that he did not actually know that the first tweet came from the person he had said it had. Maybe he then hurriedly deleted the original tweet. I hope he did.
The potential legal repercussions of those 140 characters took my breath away. Repeating a libel is, as every hack knows, just as bad as originating it. Repeating a libel and then attributing it to someone who didn't say it is off the scale.
The phone-ins this morning are all about making the press behave. I think the drift of the business will probably take care of that on its own. If it's no longer about moving paper from a shelf there will be less call for the lurid headlines which are the endgame of the controversial stories.
Maybe Twitter is the tabloid of tomorrow, the place where people will gather to share stories which confirm all their prejudices. But just as the press is going to matter less, social media is going to matter more and everybody is going to have to make sure their fingers aren't quite so tappety-happy.