Massively multiplayer online game A massively multiplayer online game ( a . k . a . MMOG or simply MMO ) is a type of computer game that enables hundreds or thousands of players to simultaneously interact in a game world they are connected to via the Internet . Typically , this kind of game is played in an online , multiplayer - only persistent world . " World of Warcraft " is a " MMORPG " , a type of MMOG or MMO . MMOGs compared to other computer games . There are a number of factors shared by most MMOGs that make them different from other types of computer games . MMOGs create a persistent universe where the game continues playing regardless of whether or not anyone else is . Since these games strongly or exclusively emphasize multiplayer gameplay , few of them have any significant single - player aspects or client - side artificial intelligence . As a result , players cannot " beat " MMOGs in the typical sense of single - player games . One exception is " Star Sonata " , a free - download MMOG located at http : / / www . starsonata . com . In this game , you take control of a space - faring vessel , and through trade and negotiation , you can be crowned " Emperor " and " win " the game . Nonetheless , you will find lots of NPC s and Mob s in most MMOGs who give out quests or serve as opponents . ( see Timesink s ) Most MMOGs also share characteristics that make them different from other multiplayer online games . MMOGs host a large number of players in a single game world where all those players can interact . Popular MMOGs might have thousands of players online at any given time usually exclusively on a company owned server . Non - MMOs , such as " Battlefield 1942 " or " Half - Life " usually have less then 50 players online and are usually played on private servers . Also , MMOs do not have any significant mods since the game must work on company servers . MMOs are special in having spawned virtual economies of game items , something that other game types have not yet created . There is some debate if a high head - count is the requirement to be a MMO . Some say that it is the size of the game world and its capability to support a large number of players that should matter . For example , despite technology and content constraints , most MMOGs can fit up to a few thousand players on a single game server at a time . Given technology development online multiplayer may eventually become MMOs as well as the average server size increases . However , by then the benchmark may have increased as well and MMO ' s will host many times even that . Alternatively , if the defining characteristic of MMOs is that all the players must be in a single - world where they can interact , online games with a highly fragmented un - connected sever base are not MMOs . To support all those players , MMOGs need large - scale game worlds . In MMOGs , large areas of the game are interconnected within the game such that a player can traverse vast distances without having to switch servers manually . For example , " Tribes " comes with a number of large maps a server plays in rotation ( one at a time ) , but in the MMOG " PlanetSide " all map - like areas of the game are accessible via flying , driving , or teleporting . There are few more common differences between MMOGs and other online games . Most MMOGs charge the player a monthly fee to have access to the exclusive servers . The game state in a MMOG rarely resets ; what the player earned yesterday is with them still today . MMOGs often feature in - game support for clans and guilds , such as the ability to manage an association with in - game tools . The boundaries between multiplayer online games and MMOGs are not always clear or obvious . " Neverwinter Nights " ( 2002 ) and " Diablo II " are usually called online RPGs , but are also sometimes called MMORPGs ( a type of MMOG ) . The popularity of MMOGs is mostly restricted to the computer game market . Online games have not yet gained huge audiences on console game systems . Nevertheless , there have been several console MMOGs including " Phantasy Star Online " ( Dreamcast ) , " EverQuest Online Adventures " ( PlayStation 2 ) , and the multi - platform " Final Fantasy XI " ( Microsoft Windows , Playstation 2 , and Xbox 360 ) . Types of MMOGs . There are several types of massively multiplayer online games . ARG . Although not prefixed with " MMO " , ARGs ( alternate reality games ) are massively multiplayer , allowing thousands of players worldwide to co - operate in puzzle trails and mystery solving . MMORPG . Massive multiplayer online role playing game , known as MMORPGs , are perhaps the most famous type of MMOG . MMOFPS . Several MMO first - person shooters have been made . These games provide large - scale , team - based combat . The addition of persistence in the game world means that these games add elements typically found in RPGs , such as experience point s . The first MMOFPS was probably " 10SIX " , released in 2000 . Other popular MMOFPS games include " World War II Online " and " PlanetSide " . MMORTS . A number of developers have attempted to bring real time strategy games into the MMOG fray . Some notable MMORTS games include " Mankind " , " Shattered Galaxy " , and " Ballerium " , which is still in development . Others . Most other MMOs are apparently simulation games , such as " Motor City Online " , " The Sims Online " ( though this is often called an MMORPG ) , " Ace of Angels " , and " Jump Gate " . There are also games like " Second Life " and " There " that derive from the tradition of MUSHes , emphasizing socializing and world - building . An interesting variation from the classic MMOs is " Game Neverending " — a " game of social , political and economic actions " which was announced in 2002 and is still in closed beta . In April 2004 , the United States Army announced that it is developing a massively multiplayer training simulation called " AWE " ( asymmetric warfare environment ) that is expected to begin operation among soldiers by June . The purpose of " AWE " is to train soldiers for urban warfare and there are no plans for a public commercial release . Forterra Systems Inc . is developing it for the Army based on the " There " engine . History . The first type of MMOG was the MMORPG . MMORPGs themselves trace their roots to MUDs , Bulletin board system ( BBS ) games , and browser - based games . As computer game developers applied MMO ideas to other computer and video game genres , new acronyms started to develop , such as MMORTS . MMOG emerged as a generic term to cover this growing class of games . These games became so popular that a magazine , called Massive Online Gaming , released an issue in October 2002 hoping to cover MMOG topics exclusively , but it never released its second issue . Naming . By applying MMO to a number of different genres , and sometimes to multiple genres at once , game developers , gamers , and marketing departments have created long and obscure acronyms . One humorous example is " SFMMORPGRTSFPS " , once used to describe " PlanetSide " ( " sci - fi , MMORPG , RTS , FPS " ) . There have been a number of attempts to popularize new names , but " MMO " and " massively multiplayer " became gaming buzzwords in the late 1990s and early 2000s . " Massive Online Gaming " magazine attempted to shorten the name to just " massive online gaming " ( or " MOG " ) , but few used this version . Although , " World of Warcraft Battle Chest Guide " also mentions the term " MOG " in referring to those earlier games . MMO had entrenched itself as a selling point for many games . Another small controversy exists over whether it is " massively multiplayer " or " massive multiplayer " ( without the " - ly " ) . Some say that " massive multiplayer " emphasizes the nature of the game over how many players actually play it . Others also prefer massive since they believe that " multiplayer " is an absolute adjective and cannot be sensibly modified by the adverb " massively " ( e . g . , just like " very dead " ) . Many gamers feel that the issue is trivial . Trivia . With more than 11 . 5 million monthly subscribers , " World of Warcraft " is currently the world ' s largest MMORPG in those terms , and holds the Guinness World Record for the most popular MMORPG . In April 2008 , " World of Warcraft " was estimated to hold 62 % of the massively multiplayer online game ( MMOG ) market .