MMORPG in research

There is a famous case where the popular MMORPG World of Warcraft had been used in a research regarding pandemics. A disease called known as the corrupted blood had spread around most of the servers and had an enormous effect on players.

The media had taken particular interest in it as it may emulate real-life behavior of humans in a wake of a real pandemic. There have been studies on how real people would react had this pandemic been a real one and the studies had shown that most of the players would willingly spread the disease to others before dying themselves.

References
http://en.wikipedia.org/wiki/Corrupted_Blood

more of the story can be found here.