The history of massively multiplayer online games spans over thirty years and hundreds of massively multiplayer online games (MMOG) titles. The origin and influence on MMO games stems from MUDs, Dungeons & Dragons and earlier social games.
In 1974, Mazewar introduced the first graphic virtual world, providing a first-person perspective view of a maze in which players roamed around shooting at each other. It was also the first networked game, in which players at different computers could visually interact in a virtual space. The initial implementation was over a serial cable, but when one of the authors began attending MIT in 1974, the game was enhanced so that it could be played across the ARPAnet, forerunner of the modern Internet.
Adventure, created in 1975 by Will Crowther on a DEC PDP-10 computer, was the first widely played adventure game. The game was significantly expanded in 1976 by Don Woods. Adventure contained many D&D features and references, including a computer controlled dungeon master.
Inspired by Adventure, a group of students at MIT, in the summer of 1977 wrote a game called Zork for the PDP-10. It became quite popular on the ARPANET. Zork was ported under the name Dungeon to FORTRAN by a programmer working at DEC in 1978.