An alternate reality game (ARG) is an interactive networked narrative that uses the real world as a platform and employs transmedia storytelling to deliver a story that may be altered by players' ideas or actions.
The form is defined by intense player involvement with a story that takes place in real time and evolves according to players' responses. It is shaped by characters that are actively controlled by the game's designers, as opposed to being controlled by an AI as in a computer or console video game. Players interact directly with characters in the game, solve plot-based challenges and puzzles, and collaborate as a community to analyze the story and coordinate real-life and online activities. ARGs generally use multimedia, such as telephones and mail, but rely on the Internet as the central binding medium.
ARGs tend to be free to play, with costs absorbed either through supporting products (e.g., collectible puzzle cards fund Perplex City) or through promotional relationships with existing products (for example, I Love Bees was a promotion for Halo 2, and the Lost Experience and Find 815 promoted the television show Lost). Pay-to-play models exist as well. Later games in the genre have shown an increasing amount of experimentation with new models and sub-genres.
There is a great deal of debate surrounding the characteristics by which the term "alternate reality game" should be defined. Sean Stacey, the founder of the website Unfiction, has suggested that the best way to define the genre was not to define it, and instead locate each game on three axes (ruleset, authorship and coherence) in a sphere of "chaotic fiction" that would include works such as the Uncyclopedia and street games like SF0 as well.
Several experts, though, point to the use of transmedia, "the aggregate effect of multiple texts/media artifacts," as the defining attribute of ARGs. This prompts the unique collaboration emanating from ARGs as well; Sean Stewart, founder of 42 Entertainment, which has produced various successful ARGs, speaks to how this occurs, noting that "the key thing about an ARG is the way it jumps off of all those platforms.