This is basically an extension of my Diablo 2 article. I personally steer clear of MMO games if I can, though I did play World of Warcraft for a free grace period. I have to work through too many games to ever engage in that massive of a time sink. I instead watch people play and chat them up about the game's intricacies.
As micro-transactions continue to flourish in games, I figured I might as well take a stab at trying to explain what could prompt someone to pay money for something that is not real. The psychology of how the value is perceived, how it depreciates in a person's head, and how you stabilize growth. It's all very much Brave New World in application, which is something I wrote a fairly dark spoof on back in my fiction days. In a society where you can buy anything so long as you work at it, providing new things to buy at just the right pace becomes an art.
I wish I could get better stats on all this. All of these companies are tight-fisted with their numbers and Second Life barely qualifies as a legitimate virtual economy because nothing depreciates in value in a traceable way. Soon enough I suppose. Until then,
A Brief Discourse on How You Suck Money Out of A Person Through Game Design