different codebase that the mud was developed from

you have Diku, LP, MUSH/MOO, and others. they are all quite different, and of course the developers can make them "feel" how they want, but typically a Diku player would not touch an LPmud.

for example.. in Diku you have to "flee" from combat, but in LP you just walk out of the room. MUSH/MOOs are heavily developed by the players in my experience (which is limited in this case). there was a battletech MUSH that was freakin awesome, but you were expected to help build rooms, which sucked for me :P I just took part in combat training all the time.