Multi-players Games and Non-gaming Metaverses are Fundamentally Different
From Clay Shirky at http://valleywag.com/tech/second-life/put-your-money-on-world-of-warcraft-232525.php
"If, on the other hand, we don't start off by lumping Second Life with Warcraft as virtual worlds, a very different question emerges: why do virtual game worlds outperform non-game worlds in their adoption? This pattern is quite stable over time -- it well predates Second Live and World of Warcraft, as with Everquest (1999) quickly dwarfing the combined populations of Alphaworld and Black Sun (later Blaxxun) despite the significant lead times of those virtual worlds. What is it about games that would make them a better fit for virtual environments than non-games?
Games have at least three advantages other virtual worlds don't. First, many games, and most social games, involve an entrance into what theorists call the magic circle, a setting with simplified and knowable rules. The magic circle saves the game from having to live up to expectations carried over from the real world.
Second, games are intentionally difficult. If all you knew about golf was that you had to get this ball in that hole, your first thought would be to hop in your cart and drive it over there. But no, you have to knock the ball in, with special sticks. This is just about the stupidest possible way to complete the task, and also the only thing that makes golf interesting. Games create an environment conducive to the acceptance of artificial difficulties.
Finally, and most relevant to visual environments, our ability to ignore information from the visual field when in pursuit of an immediate goal is nothing short of astonishing (viz. the gorilla experiment.) The fact that we could clearly understand spatial layout even in early and poorly rendered 3D environments like Quake has much to do with our willingness to switch from an observational Architectural Digest mode of seeing (Why has this hallway been accessorized with lava?) to a task-oriented Guns and Ammo mode (Ogre! Quad rocket for you!)"
In this telling, games are not just special, they are special in a way that relieves designers of the pursuit of maximal realism. There is still a premium on good design and playability, but the magic circle, acceptance of arbitrary difficulties, and goal-directed visual filtering give designers ways to contextualize or bury at least some platform limitations. These are not options available to designers of non-game environments; asking users to accept such worlds as even passable simulacra subjects those environments to withering scrutiny. "