Many of the MUDs I played on are sadly long gone, but a few are still around. I still connect every so often and chat with folks, maybe do a little light RP. Some of those same friends I've been playing with, on and off, for since the early to mid 90s. Even though we're scattered all over the world, it feels like we grew up together. I suppose, we kinda did.
It always struck me odd that MUD playership kinda died off, seeing as how there are many many more people using the Internet now than there were in the 90s. Even accounting for cultural changes and technology moving on, I would have guessed that be enough new people interested in the old ways to keep the population at least level, but alas that doesn't seem to be the case.
I'm glad I got to be a part of that era.
I'm glad I got to be a part of that culture. I learned a lot dealing with the everyday disasters of Bad Old C and ended up with responsibility and management long before I ever would have in the real world. Plus, they were a hell of a lot of fun when you found a neat spot that maybe nobody had seen since it was built.
I played one called Major Mud back in the day. When World of Warcraft came out, I thought, it's about time!
[0] https://www.reddit.com/r/MUD/
EDIT: Check out this MUD, which won MUD of the Month on the subreddit above: http://www.luminarimud.com/FMud/FMud.html
The only bad thing about it was how you had to let your character grind away for days and days on end. Most people would only come back to check on their grinds for an hour then let the script go back to its work.
Also in my implementation rather than play as the original races / classes you play as Angels or Demons which can possess and play as monsters/npcs to experience different play styles without having to create new characters.
The Angel class is the default for new players and has a mechanism by which experience points are redistributed periodically from players with more to players with less which helps newer / less active players catch up / stay relevant. Veteran / active players who get tired of carrying the team can go dark side and become demons.