Forget Fox News -- the Times Online has an analysis up of Blizzard's zombies event, and their main point seems to be that you can't compare a plague outbreak in the World of Warcraft to one in real life. Risk is what defines real outbreaks, and since there was really no risk in whether you became a zombie or not, players didn't necessarily act as they would in the real world. Some players even willingly submitted to infection, which of course presumably wouldn't happen with a real widespread fatal disease.
But there are parallels to be drawn, and professors say that the zombie plague worked a little closer to real life than Hakkar's corrupted blood did (no coincidence, I'm sure, that the zombie plague was designed to be spread, while the Corrupted Blood was basically a bug). While the plague never did really infect everyone in the world, it did spread pretty quickly -- apparently there's a number you can use to track how quickly a disease spreads, and the zombie plague landed in the arena of a normal outbreak of smallpox (given, of course, that we don't know exactly how fast or how widely it spread).
Very interesting. There is still more to say about this plague, I think (and though things have slowed down on the realms, hopefully the event itself isn't completely over). But it is fascinating how Blizzard turned emergent gameplay into an official event, and how they mimicked the real-life qualities of a spreading disease (the more of it around, the more likely you were to pick it up) while still leaving the idea firmly grounded in the in-game lore. Very cool indeed.