Persistent world

A persistent world (PW) or persistent player world is a virtual world (often in a fantasy setting and often in online realms) that is used as a setting for a role-playing game. The world is (mostly) always available and world events happen continually.

Overview
The persistence comes from maintaining and developing the state of the world in the game around the clock. Quite unlike other types of games, the plot and events in a persistent world game continue to develop even while some of the players are not playing their characters. That aspect is similar to the real world where events do occur regardless if they are directly or indirectly related to a person, as they continue to happen while a person is asleep, etc. Conversely, a player's character can also influence and change a persistent world. The degree to which a character affects a world varies from game to game. Since the game does not pause or create player-accessible back-up files, a character's actions will have consequences that the player must deal with.

Persistent worlds also exist in offline games, such as Animal Crossing (and its DS counterpart, Wild World). Even though nothing happens while the game is off (due to the obvious technical constraint), the illusion of persistence is created by advancing events as soon as the game is turned on. This is achieved by the GameCube's stepping its clock at a maximally faster pace to make up for the inactive interval, as a time datum (i.e. guide) for what should have happened. Therefore, making it seems like events had occurred while the game was off.

The term gained popularity with the growth in popularity of MMORPGs. It is also the term (frequently abbreviated as "PW") used by players of Neverwinter Nights to refer to MMORPG-like online environments, such as Arkaz, created using the game's toolkit. Some users claim that the original AOL MMORPG of Neverwinter Nights was the first graphical persistent world RPG.

Types of persistent worlds
In the first type of persistent worlds, the player and all of her or his attributes are still present in the world after a player logs off, so other gamers could still interact with the player. This is the most widely used persistent world concept.

In the second type of persistent worlds, the player and some (or all) of her or his attributes are unavailable for interaction after a player logs off. This is also known as Pseudo-Persistent World.