In 1985 I consulted at AT&T. AT&T was very state-of-the-art in making sure that every employee and consultant was on their Email system. I had come there from a UNIX-aware company that made heavy use of Email, and was delighted to see that AT&T had everyone online. Then I discovered that most AT&T employees fell into two categories:
(1) Never used Email in their lives, didn’t really know what it was. (This was the majority.)
(2) Received so little Email, they rarely bothered to dial in to see if they had any.
Nonetheless, those of us who knew how to use Email managed. First we sent the message; then we called and left a message: “This is Jane Smith calling; I sent you some Email.” The only problem with this procedure was that every time you did it, it seemed INSANE!