Way back in 1978 I got my first account on an online bulletin-board system. Using my 300-bits-per-second modem, I would log into a computer somewhere in Allentown, PA, and read and reply to messages people had left for me. If there were messages I thought were particularly important, I would save copies on my home computer in a file I called "oldmail."

Nearly 25 years later, the fundamental e-mail paradigm hasn't changed much. Sure, networks and computers are a thousand times faster, and e-mail is now used not just by a few geeks like me but by hundreds of millions of people around the world. But those are only issues of scale. Deep down, e-mail is the same as when I started using it during the Carter administration. A message comes into my mailbox. I read it, and I either file it away or delete it. Although the computer helps, it's my job to be an efficient file clerk.