Great discussion going on at the Terra Nova blog, started by Robert Bloomfield. He's set to moderate a panel called "From the Laboratory to the Virtual World" at the annual meeting of the American Accounting Association, and he's prepping for the big question: "I figure that over the three days of the conference, I will be asked 300 times 'What in G-d's name is a virtual world??'"

Bloomfield and lots of others struggle to describe the phenomenon in less than 100 words, and I think he makes a good run of it:

You can think of many virtual worlds as video games that thousands of people can play at once, together. Each player controls an animated character, called an "avatar." But other virtual worlds don’t even have something you would recognize as a "game." Instead, they are more like three-dimensional spaces in which you can get together with friends to talk, watch movies or listen to music. These worlds tend to have very active economies, because they allow residents to create and sell their own content, from clothing for their avatars to software that will animate objects and store data.

A little more tongue-in-cheek (but perhaps no less accurate), blogger Jeffrey Freeman suggests: "Tell 'em they could get rich by investing in virtual property, if they play their cards right."

It's definitely an issue we should expect to confront a lot in the coming months, as virtual worlds don't seem to be ceasing growth -- what are the most salient points about the use and value of virtual worlds for play, socialization and enterprise, and how will we explain them as more and more users inevitably catch wind?

Though, if growth takes place at the rate some predict, it could be that they'll just learn by doing!