An online pass is a digital rights management system for restricting access to supplemental functionality in a product by using a single-use serial number. Online passes are primarily intended to hinder or discourage the second-hand sale of a product, and to allow the producer of a product to still return profits from second-hand copies of the product. These passes were first primarily used by the video game industry, requiring use of a code found in a game's manual or leaflets to access to certain online content, notably online multiplayer. Following criticism of the practice, several major video game publishers, including Electronic Arts and Ubisoft, began phasing out their use in 2013. A similar tactic has surfaced in the academic textbook industry, regulating use of supplemental material and other online content, with intent to prevent students from obtaining a second-hand or borrowed copy of a needed textbook. This requires them to purchase a new copy in order to use its functionality. Video games Usage The use of online passes in video games are intended to counter the popularity of stores such as GameStop, which buy and sell second-hand copies of video games. Online passes are traditionally used to restrict access to a game's multiplayer modes and other online content; they ship as single-use codes printed on inserts packaged with retail copies of video games, and must be redeemed by the user in order to access the multiplayer and online modes of a particular game. If a player does not have an unused online pass (such as when buying a used game), the player can either purchase access via their console or can access a limited trial of the game's online content. In some cases, a game may similarly come with a code that can be redeemed for free downloadable content and other items released upon or shortly after the game's launch, such as The Stone Prisoner DLC and the Blood Dragon armor set for Dragon Age Origins, the House of Valor quest for Kingdoms of Amalur: Reckoning, and a package of 20 additional songs for Rock Band 2. Alongside downloadable content, online passes add an additional revenue stream which can be used to make up for profits lost through second-hand sales, and encourage players to buy games new at retail so they do not have to pay extra to access the game's full content. Supporters of online passes and publishers using