MOO

A MOO is an object-oriented MUD. According to Canton Becker, author of "The Unofficial Moo Guide Tutorial," a MOO is:

"...just a programming language in which you design objects. Everything is an object. Rooms are objects, exits are objects, possessions are objects, even your MOO alter-ego/ avatar is an object. We'll be looking at how you (1) make objects, and (2) write verbs that allow you to do Interesting Things with those objects. I'm not going to talk too much about the philosophy of object-oriented programming (that's what the OO in MOO stands for) so let's go ahead and make your first object:"

Canton Becker's first example (of creating an object) looks like this:

'@create $thing called kleenex'

You can then go on to relate the object to other objects and define the verbs that work with the object (which is given a number by the MOO server). Effectively, you can set up how other MOO participants will be able to use or view your object.