What do you mean by a "virtual world"? While on the one hand, it is unlikely we can (or even want to) pigeon-hole our virtual world experiences and visions into neat (and irksome) boxes. But on the other hand, it is still useful to calibrate ourselves once in a while. So. What do you mean by a virtual world? What are the basic features you require of a "virtual world" to be one. To get the ball rolling, consider Richard Bartle's delphic words (Designing Virtual Worlds, New Riders Publishing, 2003).
In this context, a world is an environment that its inhabitants regard as being self-contained. It doesn't have to mean an entire planet: It's used in the same sense as "the Roman world" or "the world of high finance."
So what about the virtual part? Not to get too philosophical about it:
Real. That which is.
Imaginary. That which isn't.
Virtual. That which isn't, having the form or effect of that which is.
Virtual worlds are places where the imaginary meets the real.
At TN we seemed to have tampered with the edges of this meaning. For example, we have collectively agreed to limit our virtual worlds to ones with (lots) of human players. Accepting this for discussion here, let me ask:
- What features do you minimally require of a virtual world?
- Can some of these features substitute for others, which ones? For example, would you be alarmed if all your guildmates were replaced by chatter-bots... and you didn't know it?
- Have your expectations evolved? PBEM a vw, once? What about tomorrow?
Now the extra-credit question. If you believe in the "MM" (as in MMORPG) requirement - what about instancing? Take it to an extreme. Is Diablo (Blizzard) on Battlenet a virtual world of 40K players? And what about City of Heroes, what if you logged on one day and everyone was on an (instanced) mission? Would you still believe?