The Matrix series of films may have been full of second-rate philosophical clap-trap, but there was one interesting idea hidden among the special effects and wooden acting. In the 'real world', the hero, played by Keanu Reeves, is just an ordinary mortal. But when he enters the computer-generated world of the Matrix he becomes a mighty hero with super powers and a really rather splendid line in tailored frock coats.

That's always been the great appeal of computer games. You may be Joe Spod in real life, but when you fire up your favourite game you instantly become the hero of the hour. You can be a mighty wizard, a World War II infantryman, a sports star, or even a Jedi Knight. It's that element of wish fulfilment that makes computer games so appealing, and what has turned the computer games market into a money-making machine that's worth even more than the Hollywood film industry.

But there's a new type of game that's appeared in recent years that takes this fulfilment fantasy to an entirely new level. The Massively Multiplayer Online Role-Playing Game (MMORPG) comes closer to the virtual reality world of The Matrix than anything that's gone before. These new games are also more addictive than any other type of game and, for the companies that develop them, have the potential to become the biggest money-spinners of all time.

In this feature we'll look at what exactly these games are, how you play them and why you might just find yourself hooked.

Sharing the experience
Traditionally, many computer games have been single-player experiences, in which one person plays against computer-generated opponents, obstacles or situations. The original Quake, for example, was a classic single-player title in the first-person shooter genre, but its popularity stemmed from its multiplayer element that allowed you to play against other people over a network.

Playing against real people can be much more unpredictable and far more fun than playing against a computer, and there are now many multiplayer games that can only be played on the internet.

However, most multiplayer shooters are actually quite limited in scope. You're generally playing within a relatively small area, such as the inside of a dungeon or spaceship, and only playing with a handful of people. The game normally has a defined goal or time limit, and once you've achieved that goal, the game is over.

Massively multiplayer games go way beyond this. They attempt to create entire 'worlds': vast virtual-reality environments that can spread across several large continents, just like the real world. Another important factor is that these games create what's known as a 'persistent world' - the game doesn't end when you switch off and go to bed. It just carries on, continuously changing and developing out there in cyberspace, with new players dropping in and out of the game 24 hours a day.

But the thing that really makes these games different is the sheer number of people playing inside the game world. In an ordinary online multiplayer game, such as Quake 3, you're generally playing against no more than 10 to 20 people at the most.

The current leader of the MMORPG pack in Europe and the US is a game called EverQuest, which is run by Sony's Online Entertainment division. EverQuest has around 500,000 regular paying subscribers - hence the term 'massively multiplayer' - and there's an even bigger game in Korea, called Lineage, that seems to have half the population of Asia signed up.

You never get all 500,000 people playing EverQuest at the same time, of course, but it's not uncommon to have 100,000 or more logged on to the game at peak times. You'll also find that the game will actually be spread across a number of servers. Each server is a central computer on the internet that runs its own copy of the game. In effect, each server becomes a self-contained world of its own, with a steady population of 2,000-3,000 players. Most people will regularly play on one particular server, developing a regular group of friends, and maybe even becoming an important figure in the politics of the game world.

Playing the game
The nature of that world varies from game to game, although most current MMORPGs follow the swords-and-sorcery template laid down by EverQuest and its main rival, Ultima Online. There are several other games that follow this format, but the most well-known ones in Europe are Asheron's Call, which is run by Microsoft, and Dark Age of Camelot, a game based on the myths and legends of Arthurian England. One of the most recent additions to this group is Shadowbane, which is currently running a free trial period, so you can try it out without committing yourself to the monthly subscription that's normally required to play these games.

The format for all these games is pretty much the same. You create a character for yourself by choosing from a variety of character 'classes', such as wizards, warriors or priests. You then send your character out into the game world to tackle a series of quests and adventures in order to gain experience and become ever more powerful. This aspect of the game is similar to old-fashioned single-player computer games, but the enormous number of players in the game adds an entirely new community dimension to the experience.

MMORPGs are intensely social games. Often, the first task for a newcomer to one of these games is to join a 'guild' - a grouping of players who help each other out, and form part of the political and social structure of the game world. Your guildmates can often become close friends, and this creates a sense of belonging that really draws you into the game world.

Many guilds have their own websites, with discussion forums and even schedules of activities that they plan to undertake within the game world on specific dates. There's one game title that really sums up the MMORPG experience. It's called Second Life, because the time you spend inside the game almost becomes a second life that runs in parallel to your life in the real world.

Wider appeal
One of the main inspirations behind all these games is, of course, Tolkien's Lord of the Rings, with its fantasy world of elves, orcs, wizards and warriors. These fantasy games found an immediate audience among hardcore computer games fans, who also tended to be fans of Tolkien-esque fantasy fiction. But this has also meant that MMORPGs have been labelled by their detractors as 'games for geeks', and it has taken several years for the MMORPG games to start to break further into the mainstream.

The only real stumbling block has been the fact that you really need a fast broadband internet connection to play these games properly. This obviously becomes less of an issue as more and more people get access to broadband services such as ADSL and cable.

There are other factors that have held back the development of this new genre. Surprisingly, though, the increased cost of such games hasn't proved to be a major problem. Most MMORPG games charge a subscription fee of around £10 a month in addition to the original cost of buying the disc(s). Players, however, will attest to the fact that you certainly get your money's worth in terms of gameplay hours. And with the potential for half a million people paying the equivalent of $12.95 a month, it's clearly a massive money-spinner for the manufacturers behind the games - to the tune of more than $6 million a month.

Galaxies far, far away
The size of that prospective market means that dozens of companies are now looking to leap onto the MMORPG bandwagon, and this year will see a whole new generation of MMORPGs competing for your monthly subscription. Games companies are also starting to branch out a bit more, in an attempt to break out of the fantasy niche and appeal to a wider, more mainstream audience.

Science fiction is an obvious source of inspiration, with games such as Anarchy Online and Neocron, that both take place in the same sort of futuristic world depicted in films such as Blade Runner. Sony has also branched out with a game called PlanetSide, which is a kind of Quake-style shoot-'em-up game, but played on a planetary scale, with large armies of players fighting to control each other's territory.

Sony clearly wants to rule the MMORPG roost over the next few years, because it's also behind one of the most important MMORPG releases of recent months. This is Star Wars Galaxies, which was developed in conjunction with George Lucas' company, LucasArts. The hope was that the pulling power of the Star Wars name (and the chance to wield a glowing lightsaber) would attract a new, more mainstream audience. The game has certainly done well, currently taking second place to EverQuest for subscriber numbers, but it doesn't seem to have made the mass-market breakthrough that the game's developers were hoping for.

But another benefit of MMORPG titles is that they are in a constant state of development, with new gameplay elements added to them as time goes on. Star Wars Galaxies has, for example, just seen the introduction of Jedi class characters and is just about to add an interplanetary vehicular element, which is likely to broaden the game's appeal immeasurably.

To infinity and beyond
Another title hoping to attract a more mainstream audience was The Sims Online, a massively multiplayer version of The Sims, the game in which you create a family of little computer people and guide them through their virtual lives. The Sims is one of the best-selling computer games of all time, and it was hoped that the online version would be a similar success. However, the online game seems to have been rushed to market before it was ready and hasn't done particularly well.

That hasn't deterred developers, though, and the next few months will see more and more MMORPGs tackling a wider range of themes. You'll be able to play the part of a lycra-clad superhero in City of Heroes, or a pirate captain in Pirates of The Burning Sea. The mighty Disney is in there too, with a kiddy-MMORPG called Toontown Online.

However, the real big hitters for this year will be two games based on massive Hollywood blockbusters. It was Lord of the Rings that got this genre rolling in the first place, and in about six months' time we should see the official Lord of the Rings MMORPG, Middle-Earth Online.

And, to bring things full circle, we'll soon be enjoying the alternative reality of The Matrix Online, a game that will continue the Matrix storyline from the end of the film trilogy.

The MMORPG genre won't go mainstream until more of us have broadband internet access, but the lure of these virtual reality worlds is getting stronger all the time, and it won't be long until you're reading newspaper scare stories about game addiction and 'MMORPG-syndrome'.

Virtual addiction
We all know that computer games can be addictive, but MMORPGs are in a league of their own. Part of the appeal of these games is the fact that the 'persistent world' in which the game takes place is continuously changing and developing. There's always something new happening, and the thought that you might miss something important is a siren call that draws you back to the game day after day.

In the US, EverQuest has been dubbed 'EverCrack' by some critics because some of its players become so addicted to the game that it starts to take over their lives. There's even a group called EverQuest Widows, which has its own forum in the Health section of the Yahoo Groups website. The group has well over 2,000 members, all telling tales of husbands, wives or children who have become compulsively addicted to the game.

Needless to say, there have already been lawsuits directed against Sony, the company that runs the game. As a result, Sony has now added a timing mechanism to the game so that it can warn people when they've been playing EverQuest for more than a few hours without taking a break.

EverQuest to join the EU?
The virtual worlds of MMORPG games are increasingly spilling over into real life. There is a thriving market in the real world for people to buy and sell items that only exist within the game world.

Take the currency used in the world of EverQuest, for example. Normally you would have to build up your character's wealth by carrying out missions and trading within the game, but a well-known auction house on the internet, www.ige.com, is offering EverQuest players a get-virtually-rich-quick scheme, by acting as a place where people can buy or sell EverQuest fortunes. The going rate is 10,000 platinum pieces for $15.

The website also trades in items such as weapons and treasure, or even virtual real-estate that is created when games players build homes for themselves inside the game world. One player who worked all the way up to the rank of fully fledged Jedi Knight in the Star Wars Galaxies game recently sold his game character for $4,000. It took him two months to build up his character, which means that it's possible to earn $2,000 a month just by waving around a lightsaber in cyberspace.

One prominent US economist, Edward Castronova, recently analysed the auctions of thousands of EverQuest-related items and came to the conclusion that the per capita gross national product of EverQuest is higher than that of Russia.