All of this may just be a precursor of what's to come. Reuben Steiger, CEO and cofounder­ of the company Millions of Us, which helps businesses understand virtual worlds and take advantage of their possibilities (an indication in itself that the real and virtual economies are becoming increasingly intertwined), envisions auto companies actually letting users of virtual worlds design cars. "They'll have a competition, and the one that is most popular will be a concept car and go into production, hypothetically," he says. "I think it ties into the whole cultural zeitgeist of the wisdom of crowds and the ability to use distributive systems to do things that even the smartest individuals can't do."

While Castronova can see plenty of ways that the virtual and real-world economies intersect, he's far from convinced that companies have much of a clue about how to operate in places like Entropia and Second Life. Even advertising and raising brand awareness, probably the most doable ventures thus far, can be done in a way that is strongly rejected by virtual-world participants. A hard sell is just asking for trouble because, as Castronova points out, people in virtual worlds have complete control over everything, including the advertising message you might be trying to send. "I think few businesspeople understand how empowered users feel themselves to be. They tolerate nothing - nothing - that they don't choose themselves," he says. "Think about the era of TV. It was possible to send an image into the living room and control it. And what is happening with virtual worlds is the image is coming right off the TV and the people are holding on to it, and they can toss it around and jump up and down on it."