Anarchy Online is a massively multiplayer online role-playing game (MMORPG) published and developed by Funcom. Released in the summer of 2001, the game was the first in the genre to include a science-fiction setting, dynamic quests, instancing, free trials, and in-game advertising. The game's ongoing storyline revolves around the fictional desert planet "Rubi-Ka", the source of a valuable mineral known as "Notum". Players assume the role of a new colonist to Rubi-Ka. With no specific objective to win Anarchy Online, the player advances the game through the improvement of a character's skills over time. After ten years, Anarchy Online has become one of the oldest surviving games in the genre.

Fighting for military and political power on Rubi-Ka are the Omni-Tek corporation (owners of the planet's one thousand-year lease), the Separatist Clans, Terrorist groups, extraterrestrial life, and ancient civilizations. The narrative was developed to be played out as a series of virtual "role-play" events over the course of four years, influenced by the actions of those taking part in the game.