Last year, I petitioned Blizzard for information about the World of Warcraft economy. As would be expected, I did not receive a reply. The fact that EVE Online is on it's way towards challenging Statscan makes me quite happy. The article is worth reading in entirety. (HT: MR)
Even so, I don't fundamentally see online games transforming the study of macroeconomics, as Alex Tabarrok suggests. People fundamentally play games in a realistic manner (i.e. with objectives consistent with real-world ones, such as profit maximization), because they are fun. Sure, there are going to be a number of good chances to witness purely exogenous shocks and see how people react (like when EVE introduced new mining technology, or when WoW released an expansion), but I doubt that macroeconomics will be able to start fundamentally answering a lot of questions that depend on unknown parameter values because people have started to game together. EVE is not going to resolve the slope of the Laffer curve, the marginal excess burden of taxation, whether a short-run Phillips curve exists, etc, etc.
I see lots of new models, especially those in topics like transport costs, but I don't see any answers that reasonably well-informed people outside of academic economics looking in could really care much about.