Actually, Los Alamos built a virtual world recently, with people running errands, going to work, and so on, and then proceeded to unleash smallpox within it: it is called EpiSims (more can be also found here with details on the Scientific American article). They even tried different vaccination strategies to see which ones worked better. But yeah, creating an online world for this would definitely save the government the trouble of simulating individuals. Perhaps this would be best in the Sims?

Each type of world offers a different value, I think. In the Sims, you have partial control over the people -- you can direct them where you want, but they have A.I. and will sometimes behave unpredictably. That might be kind of cool, though: With players only having "limited" control over their Sims, it might better simulate the panic, paralysis and/or impaired decision-making of a true crisis.

With WoW, each avatar is under direct control, so each avatar responding precisely as the player wants it to. Not sure if that'd necessarily give you a better sim, though.

Is this a game from which real economies have sprung up? It would be cool to see what effect the plague would have on the value of a virtual property covered in bodies, or on something that increases your power, etc...

There is a fairly active trading economy for things like potions or currency, but "property" is pretty limited in the game -- most of the important stuff, like a pet animal or rideable mount, isn't transferrable from one person to another. And there are no houses or domiciles or whatnot, as with, say Ultima; and when you die your corpse can't be looted. Thus, I think the economy of WoW is significant, but not centrally important the way it was to Everquest.

Usually the parallels between MMORPGs and the real world creep me out, but this is fascinating. I'd like to see Blizzard deal with it in-game, like have NPCs distribute cure potions or some equivalent. (Are there even hospitals in Warcraft?) It would preserve the "virtual world" experience a lot more than just fixing it with a patch. Besides, where's the fun in that?

If you enjoy that sort of thing, there's a catchy machanima of the WoW plague over here.

One of the most interesting things about the plague was the commentary on Blizzard's WOW community forums. Many players loved this bug...they thought of it as a FEATURE. It was an unscripted event and one where a players actions in one part of the game had unforseen ramifications in distant unrelated area's. Players could self-organize to attempt to cure/contain/spread the plague.

The WoW lore is completely prescripted, and new content has been coming out too slowly to keep the storyline engaging. The plague was like one big GM generated event that touched almost every player in the game.

Ten-Hut! Attention! Battle Stations! CLIIIIIVVE!!!!

A Giant squid has been caught alive on camera! C'mon man, you OWN this story!
http://nytimes.com/2005/09/28/science/28squid.html?hp&ex=1127880000&en=f6e2dacf29b9c0ff&ei=5094&partner=homepage

Also, Silo and Roy, have broken up. Luckily someone has made a chart of their love entanglements which Gawker has been kind enough to put up and comment upon.

http://www.gawker.com/news/penguins/we-hear-ray-got-cold-feet-127623.php

(sorry to clutter up the WOW-plauge comments with this, but I figured it was important... and goddamn that WOW plague is cool.)

Though the WoW economy (and associated Real Money Transactions or RMT) isn't as complex as in Everquest or other worlds, an aspect of the plague worth noting is that the plague tended to be spread at auction houses, where players gather to trade. I wonder if that had any effect on the economy. Trading WoW items/money outside of the game (ie through eBay or other means) is against Blizzard's EULA, but I'm wondering if the demand for a place to trade in the absence of the auction houses drove anyone to outside resources (even if only for a short time). That might have even driven up prices causing temporary fluctuation in the exchange rate between WoW gold and real money. (Has Ted Castronova looked at this at all?)