“While I was at BlizzCon, I met someone who worked at Blizzard in their IT department, and the stories he told me (all off the record, unfortunately) about how gigantic and powerful their systems are were just mindboggling. I had to ask if he knew of anyone or any other industry shooting information around at the scale that Blizzard does, and with the one possible exception of Google (who also run digital information around at a staggering rate), we couldn’t think of anyone doing things at this scale. Not even financial networks and health care information (things, you’d think, that would be much more important than your level 73 Hunter and his gear) have these kinds of systems running.”

The supercomputers behind World of Warcraft – WoW Insider