Not much is known about ARGs, because (among other things) ARGs are different things to different people, and they keep changing. However, we know how important it is to have a shared starting point. So, a couple of ARGologists — mez and J. James Bono — have bravely ventured into (cue evil echo) MEANING MADNESS and returned with a handy definition:
Alternate Reality Games (ARGs) tell stories through narrative elements that are distributed across various platforms. These game variables are carefully concealed from players until appropriate moments determined by the game designer(s). Game play involves players working collaboratively through email, phone/sms contact, real-time interactions and extensive online engagement. Players generally react to narrative cues that are projected across numerous forms of media. These include media technologies that are not traditionally associated with games that, unlike ARGs, rely on a single platform for communication (eg console games). In doing so, ARGs make players step outside the restrictions of mono-genre game boundaries.
Instead of requiring the player to enter a fictional game world, ARG designers attempt to enmesh the game within the fabric of the player’s real world by harnessing as many media technologies and interfaces as possible. By doing so, ARGs expand the frame for the game beyond the computer monitor or television screen, effectively making the entire world the “game board.”
They intend to develop this definition and invite your thoughts, and own definitions. They also recommend checking out other great definitions around, such as Brooke Thompson’s description; Adam Martin and Tom Chatfield’s definition in the 2006 IGDA ARG SIG Whitepaper; and the wikipedia definition. Also check out Wendy Despain’s FAQ section on this site. And hey, while you’re at it, what about sharing a video of what ARGs mean to you?