There's an interesting piece over at Terra Nova on Amazon.com's Askville, an online question and answer forum with a slight twist - you gain experience points and quest gold! For what purpose? Good question - the author tackles the purpose and ramifications of this sort of virtual incentive system with a lengthy essay and plenty of links that I spent a while clicking my way through.
The question we might ask is: why would this matter? Other than for tax purposes or interpreting the language of wagers, do we really need to place those beads neatly in one of two boxes: money or esteem?
If you can exhange Quest gold for an Amazon gift card, then it is money. But if it also "show[s]everyone how active and helpful you've been on Askville" then it is also something else—a token of esteem. So, like many status markers out there that people might pursue ..., Quest gold belongs in both boxes at once. Prizes have valences in market, reputation, and ludic economies.
I am far from an economist, but the spread of RMT and other in-game economic developments, as well as "ludic" transactions in non-game settings, is interesting to ponder - will the application work outside of games? Do people buy into it? An interesting piece that's worth a read through (and some clicking on the links if you have time).
World of Answercraft [Terra Nova]