There are numerous password-stealing trojans specifically designed for World of Warcraft and other massively multiplayer online games. The passwords are used to steal gold and other items from victims so that it can be re-sold online.
Now eBay has decided to ban the auction of virtual goods. Actually, it's a more aggressive enforcement of already existing policy. It should be interesting to see just how this change in the re-sale market affects the source of supply. Demand is unlikely to change and so sites such as ige.com will be the short-term beneficiaries.