It's funny how core of a service the idea of email is...even pre-internet. Once companies started supplying dumb terminals connected to the corporate mainframe

It's funny how core of a service the idea of email is...even pre-internet. Once companies started supplying dumb terminals connected to the corporate mainframe on every executive's desk, "electronic mail" quickly supplanted paper memos. In my college OS class we had to build a *nix-like OS from the ground up and one of the required basic services we had to build was user-to-user messaging. After hacking out basic versions of "ls" and "cat" that was pretty much what we built next. What was not so obvious, and much harder to do, and required something like the internet to solve was system-to-system mail transfer, which Tomlinson created. It turns out to be a strangely hard problem to do well. It's not hard to get it up and running, but the edge-cases and abuses have plagued us ever since. Maybe the problem is humans.