Duping

Duping refers to the practice of exploiting a bug in the game software to illegitimately create duplicates of unique items or currency in a persistent online game, such as a MMOG. This method of cheating has been used in Diablo and Diablo II to generate copies of items, including rare or unique artifacts. Duping can vastly destabilize a game economy or even the gameplay itself, depending on the item duplicated and the rate at which duplication occurs.

Duping was also at the center of a mass banning of players on Star Wars Galaxies. In Galaxies some characters learned how to dupe the currency, "credits". Sony Online Entertainment banned players who possessed duped currency. It is alleged that people who were not directly involved in the exploit, but who accepted duped credits in legitimate trade were also banned. In reaction to what was perceived to be a an unjust punishment, several players joined a mass demonstration at a central location. Sony Online Entertainment responded to the disruption caused by the large gathering by teleporting all player characters involved away from the demonstration area (a popular on-line urban legend is that many player characters were teleported into space, essentially killing them. Although evidence as to whether or not this occurred cannot be substantiated, it has been voiced in many popular gaming avenues, such as Penny Arcade).

Another method to mitigate the effects of duping would be a game-wide rollback, in which all the data in the game world is reset to an earlier data backup prior to the first known instance of duping. This could be a highly unpopular decision with the gameplayers and is best done before much time has passed.