Klietz wrote a game called Milieu using Multi-Pascal on a CDC Cyber 6600 series mainframe which was operated by the Minnesota Educational Computing Consortium.
Not all MUDs are games; some are designed for educational purposes, while others are purely chat environments, and the flexible nature of many MUD servers leads to their occasional use in areas ranging from computer science research to geoinformatics to medical informatics to analytical chemistry.
Most MUDs are run as hobbies and are free to players; some may accept donations or allow players to purchase virtual items, while others charge a monthly subscription fee.
Scepter supported 10 to 16 simultaneous users, typically connecting in by modem.
It was one of the first commercial MUDs; franchises were sold to a number of locations.
The game was significantly expanded in 1976 by Don Woods.