Duplication

Duplication (or 'duping') refers to the practice of taking advantage of an incorrectly coded (known as a bug) piece of a video game to falsely obtain or create duplicates of unique items or currency in a persistent online game. Duping by players has a vast number of effects; one of which is the destabilization of a virtual economy or even the gameplay itself, depending on the item duplicated and the rate at which duplication occurs.

Duping is considered to be a game cheat as the process is not a published game process for players, nor does it adhere to ingame rules as laid out by the game owners upon publication or amendment thereafter.

DDO has experienced multiple waves of duping. Many have involved using code vulnerabilities in one or more of the following:
 * Bags
 * Green Bags
 * Red Bags
 * Festival bags
 * Cookie Jars
 * Card Bags
 * Shared Bank
 * Crafting interfaces

Duping is against the game rules. When players are caught duping they are then subject to a temporary (which is rarely permanent) game ban and their inventories are usually cleared with.