I recently encountered a book called "E-Mail Addresses of the Rich and Famous," by Seth Godin, that describes how to contact many well-known people by electronic mail. My own address (yes, I am the famous and charismatic moderator of comp.sys.amiga.reviews :-)) was incorrect, so I e-mailed a correction to the author, whose address was given in the book. My e-mail bounced back with the error message, "undeliverable message."
(From the "Rest" of RHF)