Modeling Epidemic Spread in Synthetic Populations - Virtual Plagues in Massively Multiplayer Online Games

Some games, such as The Sims, encourage mods (including virtual plagues) and the game has a huge community of modders. In one famous case, the guinea pig mod [15]; one of the first recorded virtual plagues, the culprit turned out to be the chief game developer Mr. Will Wright himself [10]. This opened for a discussion about the responsibility from the game developer side as to acknowledging the time and effort put in by people into their game characters, including not only virtual plagues but also, e.g., keeping servers alive in spite of declining numbers of players. The very first mods were made by Wizards (and players with access to the underlying text databases) of Multi-User Dungeon (MUD) in the late 1980s [11]. The most famous example of virtual plague initiation from the developer side is perhaps Blizzard's introduction of the Corrupted Blood debuff in World of Warcraft. This debuff was originally conceived of as spreading from monster to player only, although Blizzard let it transmit from player to player if the players were standing close to each other. The idea was to let one boss monster issue the debuff, which would then be allowed to affect all players fighting that particular monster (and ultimately help kill off another boss monster in the same area). What was unexpected, and seemingly a surprise to Blizzard, was that players passed the debuff on to their pets, dismissed the pets, and then resummoned them later, in much more populated areas. This led to tens of thousands of deaths on at least three servers, and caused Blizzard to try to correct the problem through various quick fixes (cf.