Diablo III's Auction House, which lets players sell items for either virtual gold or real currency, has been a difficult experiment since the beginning. Now, it's been temporarily pulled completely offline after a patch bug allowed users to accumulate billions or even trillions in gold. Patch 1.08, which went out to American servers yesterday, included an economy-breaking bug: players found that if they put up a gold auction and then canceled it, they'd be refunded twice the amount they put up. Compounding the problem was an update that changed the maximum stack or transaction size from one million to ten million gold, allowing much larger sales at a go.

The result, according to forums, was sudden hyperinflation. One poster describes a player with 371 trillion in gold, and others describe buying gems or other items and taking advantage of the influx in cash to flip them for huge amounts of in-game money. The increased stack size meant that massive amounts of gold could be sold for very little real-world money, and players complained that the in-game cash they made had become useless.

In response, Blizzard developed and implemented a fix for the duplication bug, but it was left with the problem of how to fix Diablo III's economy. Many players asked for the servers to be rolled back, essentially erasing all the events of the last day. Blizzard, however, said that the problem wasn't widespread enough to justify a rollback. "We feel that this is the best course of action given the nature of the dupe, how relatively few players used it, and the fact that its effects were fairly limited within the region," a moderator wrote.

Instead, Blizzard will apparently be trying to undo the damage by targeting people who took advantage of the bug. "We've been able to successfully identify players who duplicated gold by using this specific bug, and are focusing on these accounts to make corrections. While this is a time-consuming and very detailed process, we believe it's the most appropriate choice given the circumstances."

Diablo III's economy can't touch that of the long-running World of Warcraft, but the Auction House has been a major part of the game since the start, replacing third-party sites and letting players spend and make real money. In fact, the meta-game it introduces has become a point of regret for Diablo III's director Jay Wilson. "I think we would turn it off if we could," Wilson said at GDC in March, calling both the gold and real-money auctions a bad move for gameplay. "We were kind of guessing at the impact it would have and it had a much bigger one than we expected."

Virtual economies can be both big business and microcosms of real-world situations, and building a good game economy requires just as much thought as putting together the more difficult mechanics. Valve, for instance, keeps economist Yanis Varoufakis on staff to deal with things like in-game bubbles that can leave players "heartbroken." Right now, Diablo III players aren't so much heartbroken as deeply indignant, calling out both Blizzard and "profiteers" who have taken advantage of the bug.