MMORPG

Massively multiplayer online role-playing game (commonly abbreviated MMORPG) is a genre of computer role-playing games in which a very large number of players interact with one another within a virtual game world.

As in all RPGs, players assume the role of a fictional character (often in a fantasy world), and take control over many of that character's actions. MMORPGs are distinguished from single-player or small multi-player RPGs by the number of players, and by the game's persistent world, usually hosted by the game's publisher, which continues to exist and evolve while the player is away from the game. This is often referred to being offline, or AFK (away from keyboard).

MMORPGs are very popular throughout the world. Worldwide revenues for MMORPGs exceeded half a billion dollars in 2005, and Western revenues exceeded US$1 billion in 2006. In 2007 and 2008 the virtual goods buying and trading has increased dramatically. Next to the more traditional subscription model, virtual goods are a second source of revenues for publishers. In 2008, Western consumer spending on subscription MMOGs grew to $1.4 billion. World of Warcraft had over 11 million subscribers as of 2009.

Usually there was few server host this game as I know there was private server that usually host by individual or game maniacs (lol ^^), local server usually host by local game company and international server. since the game has both side server side and client side, there always been a lack that can be exploit by cheater even the game had a gg (game guard).

source : en.wikipedia.org/wiki/Massively_multiplayer_online_role-playing_game