Virtual Gaming's Elusive Exchange Rates

CNet has published an article entitled "Virtual Gaming's Elusive Exchange Rates", in which they discuss the difficulty in putting a fixed exchange rate on MMORPG coinage. The article also points to a site called GameUSD, which provides graphs showing the cost-per-coin fluctuation in several of the top MMORPGs. Interesting stuff:
Here's how it works: Since most multiplayer games allow players to transfer their virtual gaming possessions, enterprising players can temporarily leave the gaming world and buy and sell their virtual currencies on exchanges like IGE and auction giant eBay.

Players looking to sell or buy typically use the secondary exchange sites to find one another. On IGE, for example, a buyer and a seller can strike a deal for 10 million "Ultima Online" gold pieces and exchange real dollars for them. But in order to transfer the fantasy gold, they have to meet up back in the gaming world for the handoff of the goods.

IGE also acts like a middleman, buying with real money fantasy coins from game players and, in turn, selling them to other players.