For all the differences among them, the juggernauts of social media rely on a common business model: create free services, then sell ads against users' information. In a dramatic departure, a new social network plans to give its users a 50 percent commission—or even let them sell their own ads and keep all the revenue.

Chime.in is built around users' interests—think photography, politics, or travel—as opposed to friends, professional contacts, or news. The site's founders hope that by creating pages around those interests, the users will attract people with similar affinities, an attractive combination for targeted advertising.

"Because social is going to be so powerful, I feel that the people who are creating the engaging social content should have some stake," says Bill Gross, the serial entrepreneur who is the CEO of both Idealab, a startup incubator, and Ubermedia, a social media developer that launched Chime.in. "Right now that's sort of a heresy—but I almost like it that people think it's heresy. It gives me more of a lead."