Diablo III's auction houses "really hurt the game," former game director Jay Wilson said at a GDC talk in San Francisco attended by Joystiq. The gold-based market and real-money auction house were meant to combat external trading services and interest a small subset, but they ended up spoiling the campaign.
Wilson said Blizzard thought only a small percentage of players would use the online markets. But once the game went live, it found nearly all players auctioned, and half of them did so regularly.
The auction houses impacted all levels of play profoundly; money became a greater motivator than killing Diablo, and item rewards became meaningless when players found they could easily buy gear superior to that which they looted--with cash or, more commonly, with their extra gold.
"I think we would turn it off if we could," Wilson said, but it's unfortunately "not as easy as that." Blizzard isn't willing to just shut off a system which many players might still enjoy. Wilson said the team is working on more viable options, but did not elaborate.
The PlayStation 3 version of Diablo III has no auction houses to begin with.