Email might be just responsible for the productivity increases that economists tell us are the key to rising prosperity. But it could also be sending us all mad. 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 hide behind silent, typed communications. The trouble is that the recipient of an email does not hear a tone of voice or see a facial expression; nor can the sender modify their message halfway through, sensing that is causing offense. When you read an email, you cannot tell the mood of the emailer.

A permanent written form is deadly if you are feeling impetuous and emotional. Too often I have made the mistake of sending an irritable response, which will have festered and angered the other end much more than a difficult telephone exchange. Spoken words fade, but email is forever.

It is so much easier to be tough via email, or to get away with weak excuses, or to make things up, or to say no. Almost invariably, it is more human and serious to have a real discussion rather than a bizarre online conversation. I know employees who have been hired for sending abusive emails, or who have faced severe legal consequences for writing something they should have said verbally.

Everyone in business finds their inbox is almost swamped every day with spam. I notice I spend longer and longer sorting out the emails that matter from all the junk. It has become, I’m afraid, a dangerously corrupted medium. Large companies suffered chronic overuse of ‘reply to all’.

It must be admitted that email is hard to beat as a transmitter of documents and data. It forces the sender to carefully think through their arguments and express themselves logically. It allows you to reply swiftly to a host of different questions when time is short. You don't have to worry about the journey times or travel costs, unreliable postage, or engaged phones or voicemails.

Email is a marvelously economical tool for keeping in touch with far-flung commercial contacts; you can send them a note at your leisure, 24 hours a day. It is also a terrific method of discreetly and directly pitching to someone powerful . It certainly beats trying to get a meeting or even reach them on the phone.