Although "massively multiplayer online game" (MMOG) was an obscure term at the turn of the century, these days it's applied haphazardly to an increasingly broad spectrum of games with multiplayer capabilities. No doubt, World of Warcraft has raised the profile of MMOGs to a point where everyone seems to want to jump on the massively multiplayer bandwagon. But are all these games, even those which use a lot of "instancing," really MMOGs? While there is no concrete definition of MMOG to resolve the issue, I think the proper use of the term MMOG deserves further examination.
A Brief History of "Massively"
The term MMOG or MMORPG first appeared around 1995, and was used to describe games like Interactive Magic's Air Warrior flight simulator, which allowed up to 100 pilots to take flight in the same virtual sky. A year or so later Trip Hawkins pitched 3DO's Meridian 59 as a massively multiplayer game, and it was also used to market Ultima Online, which was released in 1997. The term didn't really become widespread until EverQuest took off several years later and it was clear that graphical MMOGs were here to stay. The acrynom is often abbreviated as "MMO," and several different genres of game have been adapted to the concept, including roleplaying games (RPG), first-person shooters (FPS) and real-time strategy games (RTS).
How Many is Massive?
One common characteristic of MMOGs is that they allow you to play along with large numbers of other people in the same game environment. As usual, the devil is in the details, because not everyone agrees on what "playing" or "large numbers" really mean, and evolving technology has made these terms even more difficult to define.
While play usually involves some sort of combat, it could, in theory, also include things like trading and negotiating. Even if a game caps the number of players that can engage in a single battle, there is rarely a limit on how many players can partake in economic aspects of the game. However, I don't think this really does justice to what is meant by massively multiplayer. By this account, a game like Battlefield 2, which offers a persistent stats system even though matches have relatively small player limits, might be considered a MMOG. Similarly, if thousands of people are competing for a high score in a game of Pac-man, that doesn't make Pac-man a massively multiplayer game.
Another thing to consider is that, text-based games excluded, there are limits to how many players existing technology can handle. With a few exceptions, graphical games split their user-base across a number of different servers, also referred to as "shards" or "realms," each of which is a complete version of the game world. The population limits of servers vary from game to game, but they frequently support several thousand players each.
World of Warcraft is one game where everyone on a realm could all decide to congregate in a single zone, and there have been in-game events, such as the opening of the Gates of Ahn'Qiraj, that brought very large numbers of players into one place. In these situations, the lag inevitably escalates, information gets lost, characters near your own stop getting rendered, and the server begins to drop connections or crashes altogether. The problem is that each additional character in the area increases the amount of data that must be sent to everyone exponentially - it's only a matter of time before this overwhelms the system.
While a number of games have demonstrated that it is possible to have hundreds of active players in a single area, many games make an effort to spread players out in order to minimize lag. This is often done with instancing, which I'll discuss in a moment.
