Massively Multiplayer Online Games (MMO) are played on the Internet by necessity and are capable of supporting large numbers of players, often hundreds to thousands simultaneously. MMOs must always have at least one persistent world to be qualified as MMO. They can be found for most network-capable platforms, including the personal computer, video game console, or smartphones and other mobile devices.
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.