“Twitter is like a village or suburban bar”, writes Umberto Eco in a fascinating essay, I tweet, therefore I am (Twittero ergo sum!). “You hear the village idiot, the small landowner...and occasionally there is someone with a few sensible ideas. But it all ends there. Bar room gossip never changed international politics,” he elaborates. It is part of his latest, posthumous collection of essays, Chronicles of a Liquid Society.