Diablo 3's auction houses "really hurt the game" and Blizzard would shut them off "if we could", according to former Diablo 3 Game Director Jay Wilson.
Diablo 3 has two auction houses - one which deals in real money and another in in-game gold - through which players can buy and sell in-game items.
It was expected, Wilson noted during a GDC talk (via Joystiq), that a legitimate auction feature would reduce the use of fraud and black market sales, and that only a small number of players would use them.
The developer was wrong on both accounts, admitted Wilson. Almost every Diablo 3 player, he said, has used an auction house at some point, and over half of them on a regular basis.
This "damaged item rewards", he added, and the pursuit of money has detracted from what should be the game's real motivator - its campaign.
Wilson goes on to admit that the firm would ideally deactivate the auction houses. "I think we would turn it off if we could," he said, but suggests that it's "not as easy as that" since doing so could upset a large portion of the game's user base.
In February publisher Activision reported that Diablo III had sold more than 12 million copies worldwide as of December 31, 2012.