The experience of surfing the Internet could be improved if users were given more guidance and camaraderie, says Merci Victoria Grace, chief creative officer and cofounder of the startup GameLayers, based in San Francisco. Users surf alone, wandering through piles of data without enough chance to interact with it, or with each other.

To make surfing the Web a more social and lighthearted experience, Grace and the company’s other designers are grafting a massively multiplayer online game on top of ordinary Web browsing. Players rack up points as they visit sites, devise themed missions that lead other players through sets of websites, and leave notes for one another–all of it invisible to nonplayers. GameLayers calls its game PMOG, for “passively multiplayer online game,” because “we’re layering games on top of things that are already there,” says CEO and cofounder Justin Hall, known for his pioneering blog, Justin’s Links from the Underground, and for his work as a freelance journalist. “The model for the game is that people can opt to play at any moment,” he says. As in other massively multiplayer online games, PMOG brings each player into the experience of participating in a single vast game, taking place across the whole of the Internet, 24 hours a day. Players can gain tools and abilities as they progress, but there is no end to the game.

To get started, players download a toolbar. When they log in to PMOG, software tracks the sites that they visit, and gives them points for each unique URL they visit within a 24-hour period. Then they can create and take missions. For example, a PMOG player might visit the homepage for the forthcoming Batman movie, The Dark Knight, and find a pop-up from a fellow player inviting him to learn about the history of Batman. If the player elects to follow the mission, a series of pop-up windows would lead him through sites where he might, for example, view cover art from the Batman comic books, read trivia on the Batman TV series, and view information about the making of the new film. At each site, he’d find pop-up windows displaying notes written by the mission creator, perhaps giving additional background on the site, telling a story, or leaving clues to a puzzle.

Along the way, players can IM each other; leave gifts of links, points, and other game equipment; and even detonate little bombs that cause other players’ browser windows to temporarily (and harmlessly) shrink. “It’s like instant messaging meets [social bookmarking site] del.icio.us, meets Wikipedia,” says Joichi Ito, a board member of the Mozilla Foundation and a venture capitalist who has invested in GameLayers. “I think more and more people are receptive to bringing play into things that are more mundane. There’s this puritanical thing that we’re all getting over now.”

“This is a video game that’s designed to fit into your everyday life,” says Alice Robison, a researcher in the comparative media studies department at MIT. “It blurs the boundaries between playing a game and playing life.” Robison notes that the game is structured so that players gain tools and points based on how they behave online, rather than on a character they construct. “The score-keeping element forces you to be who you are.”

Hall says that the company is now experimenting with business models, and it’s likely to try to make money by building missions that would be sponsored by advertisers. Although the details aren’t set in stone, Hall says that PMOG would probably contain a category of sponsored missions that players could take, and players might be rewarded for taking them by receiving something like bonus points. However the business plan shakes out, Hall wants to be careful not to abuse the access to personal data that PMOG has. “Users are trusting us with their personal surfing history,” he says. “Users are trusting us with their screen real estate. We like the idea of giving them a total opt-in solution.” Hall thinks that some films, in particular, might be well suited for advertising through PMOG. He envisions one day creating similar games for mobile phones, or extending the concept to transform other types of data on the Web into play.

Similar ideas have been tried before. Third Voice, a startup that lasted from about 1999 to 2001, allowed users to annotate websites. Although the site sparked some debate among people who worried about Third Voice users leaving graffiti on websites–by advertising for competitors on corporate sites, for example–it was the dot-com flameout, not controversy, that brought down the company. Jonathan Zittrain, a professor of Internet governance and regulation at Oxford University, who was also a member of Third Voice’s advisory board, says that the demise of Third Voice shouldn’t be taken as a comment on the viability of giving users the chance to interact with Web pages and to share those interactions with others. “I think that’s exactly the feature that could be very powerful,” he says. “It will depend on how well it avoids spam, both literally and figuratively, from people that you’re not interested in hearing from, and [it] will no doubt trigger, I think, similar forms of outrage from webmasters, who want to know that the site you see is the site they intend for you to see.”

GameLayers is now testing PMOG with a small, initial group of users–about 6,000 have registered as of this week. Hall says that the game will open to the public soon, although no exact date has been set.