[jarin]

It might not be such an issue either, because with a subscription-based game like WoW, item rarity has more value to Blizzard because the longer it takes to get an item the more subscription revenue they get.

With Diablo III being a one-time purchase, item duping would devalue items on the player side and may or may not result in increased commission revenue for Blizzard (depending on how many players will actually purchase the item on the auction house).