A
massively multiplayer online game (also called
MMOG or simply
MMO) is a
video game which is capable of supporting hundreds or thousands of players simultaneously. By necessity, they are played on the
Internet, and feature at least one
persistent world. They are, however, not necessarily games played on
personal computers. Most of the newer game consoles, including the
PlayStation Portable,
PlayStation 3,
Xbox 360,
Nintendo DS and
Wii can access the Internet and may therefore run MMO games. Additionally, mobile devices and smartphones based on such operating systems as
Windows Mobile and
Google's Android, as well as the
Apple iPhone are seeing an increase in the amount of MMO games available.
MMOGs can enable players to cooperate and compete with each other on a large scale, and sometimes to interact meaningfully with people around the world. They include a variety of gameplay types, representing many video game genres.
The most popular type of MMO, and the sub-genre that pioneered the category, is the massively multiplayer online role playing game (MMORPG), which descended from university mainframe computer MUD and adventure games such as Rogue and Dungeon on the PDP-10. These games predate the commercial gaming industry and the Internet, but still featured persistent worlds and other elements of MMOGs still used today.
The first graphical MMOG, and a major milestone in the creation of the genre, was the multi-player flight combat simulation game Air Warrior by Kesmai on the GEnie online service, which first appeared in 1986.