An exchange ahead of its time

One might say that I and a friend of mine anticipated text messaging by many years.

Back in 1991 when I started the Ph.D. program, I got access to e-mail for the first time.  A friend of mine at another institution and I often exchanged messages.  My friend, being burdened by having both a wife and two children, was often too busy to send much of a message, but to show that he had not forgotten me, he would send brief messages.

One day, he sent me a message asking, "How are you doing?"

I then sent him an e-mail with the subject header "How I am doing."  The body of the message was "OK."

"Good!" my friend replied back.