Sim-O

A little quiz. What’s this about?

8^th May 1978:

1) I didn’t receive the DEC message, but I can’t imagine I would
have been bothered if I have. I get tons of uninteresting mail,
and system announcements about babies born, etc. At least a
demo MIGHT have been interesting.

9^th May 1978:

Well, Geoff forwarded me a copy of the DEC message, and I eat my
words. I sure would have minded it! Nobody should be allowed
to send a message with a header that long, no matter what it is
about.

Answer here, the quotes from here.