According to the BBC:

An outbreak of a deadly disease in a virtual world can offer insights into real life epidemics, scientists suggest.

The "corrupted blood" disease spread rapidly within the popular online World of Warcraft game, killing off thousands of players in an uncontrolled plague.

The infection raged, wreaking social chaos, despite quarantine measures.

The experience provides essential clues to how people behave in such crises, Lancet Infectious Diseases reports.

In the game, there was a real diversity of response from the players to the threat of infection, similar to those seen in real life.

Some acted selflessly, rushing to the aid of other characters even though that meant they risked infection themselves.

Others fled infected cities in an attempt to save themselves.

And some who were sick made it their mission to deliberately infect others.

Extremely interesting, imho. Using virtual worlds as templates for models in real life. I would like to see if controlled experiments could be implemented in Second Life and other places, with some of the people knowing they are part of the experiment and other group only aware that they are in a weird situation. Ideal for agalmic societies. Are we witnessing the birth of a new branch of the Social Sciences?