Gamers today, instead of being thrown into a universe created by teams of designers, can grow their own world, inhabited by any shape of creature they can imagine.
"The future of software development is user-created content", says David Fleck, from Linden Lab, the makers of Second Life.
"First and foremost it allows them to exploit their creative energies and display all the wonderful things that they're good at doing, whether it's manufacturing clothing or architecture.
"In some cases the creations are so fantastic that we even label them as being vanity creations, where they've put all their energies into something that really represents who they are."
For the industry, user-generated content has another, commercially compelling appeal.
Development costs are skyrocketing. Big budget titles can cost $20 million upwards (around £12 million), so getting the players themselves to reinvent the content saves money and extends the game's shelf life.
But there are still unresolved issues, such as who owns the user-generated content - the users or the game makers?
The makers of "shoot 'em up" game Half-Life found their own solution.
"When Half-Life came out it was a huge hit", explains Dave Kosak, editor of the games website FilePlanet.com.
"Then users out in the community created a modification for Half-Life called Counter-Strike which, even today, is one of the most popular online games.
"This game was so huge that the company behind Half-Life went back, bought the team that developed it, and then sold it in retail."
But not all gamers are sold on creating their own material. There is no guarantee that amateur tinkering in the bedroom will produce the kind of gameplay that we have come to expect.
GameSpot's Ankarino Lara says there are two big challenges with user-generated content.
Spore's code means it can animate anything you could imagine
"On the one hand it's a lot of time and energy that you have to spend to engage with a game like that and create user-generated content; people like the idea of taking a game off the shelf, popping it in, having an amazing single-player experience, cinematic, polished, professional.
"On the other side, because it's such a ubiquitous trend now, you have lots of people creating content. A lot of it's noise and trash and that is not very good."
Gaming guru Will Wright is the mastermind behind the hugely popular user-generated content games SimCity and The Sims.
For the past five years, and at a cost of $30 million, he has been developing a new game called Spore.
You can watch an extended interview with Will from the top of this page, using the link under his picture.
The idea of Spore is to create and bring to life your own civilisations, starting from a single cell organism, and eventually dominating the universe with highly intelligent species.
Breathing new life
Possibly the most innovative part of the game is its ability to bring to life creatures of any design.
In simple terms, the game is capable of figuring out the physics of how your creatures should move and interact, guaranteeing that everyone's creations will at least work.
Lucy Bradshaw, executive producer of Spore, says: "We have actually written code that has trained the computer to animate anything that a player can imagine to bring to life.
"It could have two legs, it could have eight legs. It knows how to make each of those creatures walk.
"And the thing that's really special about that is that the universe is going to be populated with incredibly unique content from our players."
Ultimately the true significance of Spore may be measured in how widely its technology is adopted. If successful, it could raise the game of user-generated content throughout the industry.
As Dave Kosak says: "It's a new way of making games. It could save a lot of money; it could create a lot of new and interesting game ideas.
"So a lot of people are watching Spore very closely."