So a MOO is a place, not a physical place, but a virtual place created on the network of networks that we call the internet. The MOO is housed on a computer, called a server, and is accessed through a text relaying client program, such as telnet, using a modem. MOOs are written in a language that is a cross between C++ and LISP, called MOOCode. MOOCode is a form of OOP Object Oriented Programming. Users of MOOs can get what is called a Programming Bit basically a level of access to the core computer that allows them to program in MOOCode. Most MOOs have information about this by typing help programming.

Website: http://cinemaspace.berkeley.edu/~rachel/moo.html