Blizzard—and other MMO developers—constantly battle individuals and organizations who seek to illegally make money based on their intellectual property.  Most commonly, these activities take the form of gold selling and after-market sales of their virtual items.  In other words, people sell in-game currency or items for real cold hard cash.  These shady transactions not only cut Blizzard out of the loop, but many times customers are cheated out of their money and then run to the developer to complain.  In a nutshell, it's a mess.  

Recently, Blizzard announced that they would allow in-game items to be bought and sold for real currency in their upcoming title, Diablo 3.  Now, it seems, they are taking further steps to combat these transactions by offering a new cosmetic pet to World of Warcraft players (for $10) that can be sold on the auction house for gold.  Previously, pets and mounts purchased in the Blizzard store were bound to the account that purchased them, but now, a player can buy a cute Guardian cub with real currency and sell them on the auction house for in-game gold.  While this won't eliminate the gold selling problem completely, it does allow players a safe and legal way to bolster their virtual wealth—and Blizzard's bank account.

[via MMO Champion]