Making money from free Diablo 3

I was wondering whether Blizzard giving away Diablo 3 has other reasons besides propping up the subscription numbers of World of Warcraft. Diablo 3 is not exactly a MMORPG, but it isn't exactly a single-player RPG either. And that applies both for gameplay, and for the business model. It is possible for Blizzard to make money from a copy of Diablo 3 they gave away for free: If the player uses the real money auction house, Blizzards takes a cut of each transaction.Whether that is a good deal for

World of Warkraft...