All in all, I'd say the MUD was a terrific place to learn to code. You could literally write a few lines of code, and see their effect immediately. "I want to code an orc." Inherit stdmonster, call a few API functions to set name and description, and BAM! - you've got an orc! And so on. Motivation never ran dry because - hey, I was adding features I wanted to a game I loved! Feedback (of varying quality, sure) was immediately available in the built in chat channel. Code was hot loaded/reloaded, so iteration cycle time was approximately zero. Emacs + angeftp (later replaced by tramp) to the host machine, you were literally editing the live code all the time (who needs pull requests when you have C-x C-s, eh?), so lots of instructive oops moments. It was amazing.
Have a whole bunch of friends with a similar story.