E-mail has revolutionised our lives, but can you have too much of a good thing? Two million e-mails are sent every second and now companies are hiring consultants to teach their staff how to cope with the daily avalanche in their inboxes. Things have got so bad that some companies have introduced e-mail-free days. Libby Potter investigates whether e-mail helps or hinders workplace performance, and shows how to control it rather than letting it control us.