It means your talking in the voice of the character your roleplaying. Imm Short for Immortal, which is the word used for the people who create and maintain diku muds. The first free mud to offer a fairly complicated programming language in which the mud itself was written. Log Certain client programs allow logs to be kept of the screen. A time- worn and somewhat unfriendly trick is to entice someone into having TinySex with you, log the proceedings, and post them to rec.games.mud.
Logs are useful for recording interesting or useful information or conversations, as well.
NPC Non-player character. MOO A type of Mud, the acyonym stands for 'Multiuser Object Orientated'. MUF Multi User Forth, it is a programming language used inside MUCKs. MUCK A roleplaying mud base. Mule Character created on goal-orientated muds those sole purpose is to supplement a player's primary character by supplying services such as equipment repair.