In a discussion with the BBC, Castronova elaborates on concepts implied by the book's title. The professor sees a lot of people withdrawing from physical reality as the opportunity to do so arises - a move the BBC refers to as an Exodus. Castronova likens this to the settling of the North American continent.
"What I tried to do in this book is say, 'listen - even if the typical reader doesn't spend any time in virtual worlds, what is going to be the impact on him of people going and doing this?'" And he predicted that everyone will be involved in a virtual environment within ten years - although the level of that involvement will vary.
In the meantime, though, he focuses on the reasons that people go online today. On the one hand you have people who go online to escape reality, to disconnect. On the other, you have people who seek to connect in ways they couldn't offline.
"A father of two spending 90 hours a week in a virtual world because he doesn't like his wife - I would say that's escapism, and it isn't anything you would say is good. "But if it's a heavy-set girl from a small town who gets victimised just because her body isn't the 'right' kind of body, and she goes online to make friends because she can't get a fair shake in the real world, then I would say the virtual world is more of a refuge."
If you're willing to share, why not add a comment letting us know why you log into your MMOG of choice?
I know for me personally ... it's both. As much as I like to think I play for noble goals (hanging out with people, accruing fodder for articles) sometimes I just hop online to get away. Whether it's money, frustrating people, illness, or what have you, it's always nice to know you have that space online. For a few hours, it's great to have your biggest worry be cranky demons or a crabby quest-giver.