E-mail might just be responsible for the productivity increases that economists tell us are the key to rising prosperity. But it could also be sending us all mad.

The truth is that business is generally best done face to face, and if that is impossible, then speaking via the phone. But too many of us now hide behind silent, typed communications. The trouble is that the recipient of an e-mail does not hear a tone of voice or see a facial expression; nor can the sender modify their message halfway through, sensing that it is causing offence. When you read an e-mail you cannot tell the mood of the e-mailer.