Identity on the web is an issue in many different ways: can he be trusted; will she misuse my details; is YahooBob the same person as YB_google; and so on. Once there was widespread celebration of the fact that anyone could be whoever they chose. Today there is widespread concern about authenticity and verification.

In his column in today’s Guardian, Marcel Berlins wrote that he had just discovered that “one of my favourite endings, to one of my all-time favourite short stories, written by my second favourite short-story writer ever, had not been written by him at all”.