Like earlier epistolary stories, the ARGs refuse to acknowledge their own fictional status. One of the key rules the group uses to sustain its "reality" is that participants never look behind the curtain. The puppetmasters -- those who create the game -- only identify themselves once the game is completed.

The content of earlier epistolary novels turned readers into armchair detectives and amateur psychologists, piecing together the events of the story from multiple, fragmentary, and sometimes contradictory, always subjective, accounts. These ARGs take on a more public dimension, exploring conspiracies or mysteries which exploit the expansive potential of the transmedia environment.

Though read in private, these early novels became the focus of parlor room discussions as people compared notes about the characters and their situations. ARGS today offer a very similar experience of mutual debate and collaborative interpretation for a society just beginning to experiment with what cybertheorist Pierre Levy calls collective intelligence.

To be sure, there have been earlier forms of collective intelligence -- people collaborating to create imaginary societies and creating relationships which extended into real world spaces. There have also been other mystery hunts -- books whose hook was that they offered clues to objects hidden somewhere in the real world.

But, ARGs push it to the next level. By design, they are impossible to solve unless people put their heads together in unprecedented numbers.

Much as some early novelists -- most famously, Charles Dickens -- published their works in serialized form and were thus able to adjust later plot developments to the public's initial responses, ARG designers react to the players. Sometimes, they needed to make a puzzle simpler, more often more difficult, depending on the community response. In an oft-told tale, players solved in a single day a set of puzzles puppetmasters for "The Beast" had intended to last a month.

McGonigal described a range of strategies she and the other designers used to insure that ilovebees could not be solved by individuals or isolated groups.

Specific bits of information were sent randomly to players, who would then have to compare notes to get all of the puzzle pieces. The game demanded mastery of obscure languages, forgotten codes, and other kinds of esoteric knowledge, insuring that no one player would have the expertise to solve it. And players were asked to do "walk and talk and chew gum" tasks that required many coordinated simultaneous actions that no single player could do by themselves. The teams became smart mobs linked by cell phones and other mobile communication technologies.

But these games do more than just send people on high-tech scavenger hunts. A well designed ARG reshapes the way participants think about their real and virtual environments.

"The best pervasive games do make you more suspicious, more inquisitive, of your everyday surroundings," McGonigal writes in an essay published online. "A good immersive game will show you game patterns in non-game places; those patterns reveal opportunities for interaction and intervention."

Much as critics of early novels worried that readers would have difficulty separating fact from fantasy or would find themselves fixating on the affairs of imaginary people, contemporary critics of ARGs worry that players will not be able to find their way back out of the rabbit hole. McGonigal and others see such critics as doing a disservice to the players who do what readers or theater goers have always done -- engage in a voluntary suspension of disbelief in order to enjoy immersing themselves into a fictional realm.

"There are killer robots and sentient houses," Stewart told McGonigal, "How could anyone be confused?"