One of the most infamous events in the history of World of Warcraft is the Corrupted Blood incident. This was an event driven by the procedure of debuffs. The Corrupted Blood debuff was part of the first dungeon released for WoW. This debuff was spread by the boss, which did periodic damage to a player until the timer ran out, the player died, or the player was cured by a fellow player.
On top of this the debuff could spread to each player in the instance, eventually infecting the whole group. Normally this would be confined to the instance, however it was found that the debuff could be carried out of the instance into the rest of the game world through pets.
This resulted in a massive shift in how players interacted with the game world. The debuff spread throughout the major player hubs and starting cities, rendering any safe zone dangerous, especially for low level players. Players began limiting interaction with others to avoid infection, while those who were infected threw caution to the wind and actively tried to infect others. Still some even took a more heroic stance and went around trying to cure everyone they met.
This incident was an insight into how people respond to epidemics. This is a case study for the behaviors of people in trying circumstances. WoW teaches us more about how humans as a population respond to events such as these. The CDC currently uses this as a study to educate its staff on how areas struck by disease might respond to it. This is also a case on bioterrorism, as people who used the debuff to spread it to others provided insight into the reasons and motivations of real terrorists.
Through this, WoW teaches us more about who we as individuals and groups are. While we have characters in fantasy settings, this virtual world is still influenced by the real world. It is a mirror in which we can see the possible outcomes of events and experience things that would be horrifying or unimaginable in reality. WoW is a wonderous reflection of humanity, showing us what kind of people we are, not through cautionary tales or distant records, but through our own actions and those of our fellow players occupying the world in the game.