I have been a happy man ever since January 1, 1990, when I no longer had an email address. I'd used email since about 1975, and it seems to me that 15 years of email is plenty for one lifetime.
Email is a wonderful thing for people whose role in life is to be on top of things. But not for me; my role is to be on the bottom of things. What I do takes long hours of studying and uninterruptible concentration. I try to learn certain areas of computer science exhaustively; then I try to digest that knowledge into a form that is accessible to people who don't have time for such study.
On the other hand, I need to communicate with thousands of people all over the world as I write my books. I also want to be responsive to the people who read those books and have questions or comments. My goal is to do this communication efficiently, in batch mode --- like, one day every six months. So if you want to write to me about any topic, please use good ol' snail mail and send a letter to the following address:
Prof. Donald E. Knuth
Computer Science Department
Gates Building 4B
Stanford, CA 94305-9045 USA.
I have a wonderful secretary who looks at the incoming postal mail and separates out anything that she knows I've been looking forward to seeing urgently. Everything else goes into a buffer storage area, which I empty periodically.
My secretary also prints out all nonspam email messages addressed to firstname.lastname@example.org or email@example.com, so that I can reply with written comments when I have a chance. If I run across such a message that was misaddressed --- I mean, if the message asks a question instead of reporting an error --- I try not to get angry. I used to just throw all such sheets in the wastebasket. But now I save them for scratch paper, so that I can print test material for The Art of Computer Programming on the blank sides. I DO NOT ANSWER UNSOLICITED EMAILS, nor do I respond to emails that were sent to my colleagues with a bothersome request for them to communicate with me. Email is a no-no EXCEPT for reporting errors in books.
`I don't even have an e-mail address. I have reached an age where my main purpose is not to receive messages.' --- Umberto Eco, quoted in the New Yorker
Sometimes I do send email, through my secretary, with respect to the project I'm currently working on, when I believe that the recipient won't be bothered by my request. But I hope you can understand why I am almost always unhappy to receive unsolicited email myself. Thank you for your patience and cooperation as I try to finish The Art of Computer Programming (TAOCP), a work that I began in 1962 and that I will need many years to complete. In return, I promise not to send unwelcome email requests to you.
Newly coined nonce words of English are often spelled with a hyphen, but the hyphen disappears when the words become widely used. For example, people used to write “non-zero” and “soft-ware” instead of “nonzero” and “software”; the same trend has occurred for hundreds of other words. Thus it's high time for everybody to stop using the archaic spelling “e-mail”. Think of how many keystrokes you will save in your lifetime if you stop now! The form “email” has been well established in England for several years, so I am amazed to see Americans being overly conservative in this regard. (Of course, “email” has been a familiar word in France, Germany, and the Netherlands much longer than in England --- but for an entirely different reason.)