1980: MUD 5 years ago
In my time with a MUD, my absolute favorite parts were: 1. Social interaction 2. Automation!
Maybe not all MUDs allowed it, but the one I played was absolutely fine with you using specialized clients such as tintin++ and writing scripts. I started with smaller scripts to automate movement between zones and managing inventory, and I moved on to full bots in there that would take "spoken" commands from trusted players.
From what I hear, that'll get you banned in most MMORPGs these days, which is a shame.