Yanis Varoufakis, Valve's new economist-in-residence, has posted his first investigation (opens in new tab) into Team Fortress 2's economy. The hat trade is more fascinating than I anticipated. Varoufakis' educational post explains (in terms non-economists can understand) two notable observations: the existence of an unusually complex barter economy in TF2, and the room for arbitrage -- buying low and selling high -- within it.
Varoufakis explains that barter economies are "cumbersome" because trades require a "double coincidence of wants" -- that is, two parties who each want what the other offers. Because of this, he says, economic complexity breeds currency, and that's why we've never witnessed "truly sophisticated barter economies." In TF2, however, the story is different.
"I was expecting to find that some item or asset would emerge as currency in the context of games such as Team Fortress 2," he writes. "However, a close study of our Team Fortress 2 economy revealed a more complex picture; one in which barter still prevails even though the volume of trading is skyrocketing and the sophistication of the participants' economic behavior is progressing in leaps and bounds."
In his exploration of TF2's "peculiarly sophisticated barter economy," Varoufakis goes on to explain the concept of economic equilibrium, and charts periods of high arbitrage potential. He outlines economics fundamentals clearly and concisely, and I highly recommend reading the whole post (opens in new tab) . Especially if you strive to have more hats and guns and stuff than everyone else.