The massively multiplayer online genre is relatively new. Games such as World of Warcraft offer things that players could previously only dream of. The game's scope, complexity, and variety of options dwarf everything that has come before. The monthly fee based structure gives companies the financial base to continue development, expanding existing games with more content, higher levels, and added complexity. Keeping these games fresh is the greatest challenge faced by mmorpg designers.

When a new mmorpg comes out, the sheer volume of content in front of a player can seem overwhelming. Time invested leads to incremental gains in resources, represented generally by improvements in various abilities and the quality of available gear. Players will progress through content at varying rates, depending on how much time they spend and what parts of the game they enjoy. Eventually, generally after several months of play, a significant portion of the player base will begin to exhaust the content of a game. This often coincides with the release of newer games that compete for player's attention. Given that most players can only find the time and/or money to support one mmorpg habit, this can lead to attrition of your highest involvement players. It is somewhat of a contradiction that the intensity with which a player approaches a game also determines how quickly he will exhaust available content.

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