Persistent Universe: Denotes any game that takes place in a constantly-running environment, even when the player is not actively playing the game. Attributes of such an environment include other players actively playing the game, game-created characters interacting with the environment or other players, etc. such that, when gameplay resumes for a particular user, the environment has changed from when the user last interacted with the environment.
Since most persistent universe games are played on remote servers, an internet connection is usually required to play them to perform updates to the game world. Part of the Non-Sports Themes category.
You can browse through games in the MobyGames database that are part of this genre via the game browser.