Back in 1925, the American periodical Harper’s Magazine claimed that “fake news” spread by radio, which was then a new medium, was “an unprecedented danger”. Almost a century later, fake news propagated by social networks is an epidemic that threatens entire political systems. Facebook, Google and Twitter have recently started combating this plague. It is not clear if these measures will be sufficient. But it is a beginning and better than allowing fake news to flourish unchecked, as was the case until recently. Facebook, for example, says it deleted over 30,000 fake accounts, which were spreading disinformation about the French