Depending on how things go from here, yesterday's date may get a sidebar in the history books or even its own chapter. It marks the release of The Sims Online, sure to become one of the most successful video games of all time and perhaps the massive multi-player computer gaming breakthrough that industry experts have predicted for years - the one that looks suspiciously, and ominously, like "The Matrix" sci-fi movie come to life.

The Sims Online is a plugged-in version of The Sims, the phenomenally successful PC video game (more than 20 million copies sold) which allows players to control digital humans ("Sims," which stands for simulations) who host BBQs, open gyms and gain points for being popular.

The Sims Online is a unique beast. In this version of the game, those other digital humans that you interact with are real people themselves, avoiding their real lives just like you, logged onto computers all around the country and, soon enough, the globe, to the delight of Maxis, Will Wright's scarily named software company, which charges a $9.95 monthly fee for the privilege.

This game is different. This is new. The Sims Online fully transcends the meaning of the word "real" and is, for all intents and purposes, an "alternate life" that users can plug into at any time. This might not be something to celebrate.

Artificial intelligence researchers identify computing environments when they program games; these environments are the game boards plus the rules. For example, chess is a complex environment: 32 pieces, 64 squares, billions of possible moves. Tic-tac-toe is a simpler environment: nine squares, a few hundred-thousand moves.

Planet Earth is, of course, the original gaming environment and perhaps the one we all should be paying attention to, to the exclusion of The Sims. For a computer to accurately simulate the complete Earth environment, it would need to take into account 7 billion lives, dense climate patterns, the secret process by which Cheez Doodles are made and so forth. This is currently beyond the reach of even the most powerful computers.

These game environments - in a computer or in the real world - are described by artificial intelligence researchers with five attributes. An environment can be "accessible" (when you know where all the pieces are, like in chess), "deterministic" (when you control everything that happens, like in solitaire), "discrete" (when everything happens in individual moves, like chess again), "episodic" (when these moves don't overlap) and "static" (when time stands still while you make your move).

A game environment that exhibits some of these attributes is relatively simple. It's easy to decide what to do in checkers, for instance, where the board is accessible, discrete and episodic.

The game of life is different. Your life is not accessible (you don't know where Osama bin Laden is, for instance). It's not deterministic (your kids decide when they fall asleep, not you); it's not discrete (you don't have "moves," as much as you'd like them); it's not episodic; and it's certainly not static.

The Sims Online exhibits none of the comfortable attributes that make a game easy. Just like real life, The Sims Online is inaccessible, non-deterministic, discrete, non-episodic and dynamic.

This is why The Sims might be the infant version of a very real, immersive cyberworld that we spend the majority of our time in in the near future. Other massive multi-player online role-playing games (MMORGs) such as Everquest fulfill the criteria too, but these games lack the environmental realism that The Sims Online brings to the table. In Everquest, after all, you've got a sword or you're a wizard or something. In The Sims Online, the best you can hope to be is a popular multimillionaire, which could happen in real life, after all.

There is something reprehensible and creepy about a video game that sucks in your actual life and gives you back a fake version at a 1-to-1 ratio. It's an aspect of The Sims Online that has been largely ignored by the media coverage of its release in favor of a more noble, no less scary pitch: that Will Wright might have just created a new society.

Do we want a Sims society? It may be too late to ask. Last week on the subway, I sat next to two women who recapped their Saturday night antics. "How come you didn't go to that party?" one asked.

"Oh, I was tired," said the other. Then, from her purse, she produced the instruction manual for The Sims computer game, not the online version (that comes later no doubt). "Have you seen this game?" she asked. "It's so addictive! It's like, I want to see how good I am at living...."