Don't know if you know that supercomputers behind world of warcraft. According to the wowinsider, we know that all the details.

The New York Times has an intriguing story up about supercomputers around the world, and, as we've heard before, some of the most powerful computers ever created are being used... to run World of Warcraft. The9, which is the company that Blizzard has licensed the game to in Asia, runs more than 10 supercomputer systems, hosting at least a million players online at a time. Some of the other tasks listed for these supercomputers include flight simulations and animation rendering -- the same type of computer that designed the wing of the plane you're flying in might have calculated just how much gold you should have after repairs.

I have a personal note to add to this one, too, though I have to be fairly vague.

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.

Very, very interesting. I'd imagine that much of what Blizzard does consists of secrets they'd like to keep (hence the reason the Blizzard employee asked me to keep much of what he told me off the record), so it's not likely we'll be able to know all that much about how they do what they do (until it's all turned off, anyway -- maybe someday we'll see a tell-all detailing how WoW was played). But man -- everything I've heard about how the game is run involves unbelievable amounts of information running inside lots and lots of servers and wires. The architecture of what Blizzard has done in terms of size and scale rivals anything Arthas has constructed in Icecrown.

Google can drop connections and redirect yo to another server at will (and does that all the time), it can give you a result from data that is 1 hour old or even a day old, it will not matter much, it can take a second or two to get the result page to you, you can only do a couple hundred Google searches per hour.

WoW needs precision, you would not be happy if you would suddenly be on another realm, if your gear or XP would suddenly revert to what it was an hour ago, if your latency would be 2 seconds (2000 ms) and still the WoW client sends hundreds of requests each minute.