The genius of Facebook—and one of the reasons it is worth more than $50 billion—is that it effortlessly collects huge volumes of information by offering people a place to socialize. Healthrageous, a startup in Cambridge, Massachusetts, thinks it may be possible to perform a similar feat in health care.

The company, launched in 2010 by physicians associated with Harvard Medical School, offers its users digital health-tracking devices including wireless pedometers, blood pressure monitors, and bathroom scales. Clients use the tools to gather data about themselves and upload it to a website where they can track progress toward goals, get wellness tips, and receive encouragement from friends, coworkers, and family members.

The startup is an offshoot of the small but growing "quantified self" movement, whose members believe that using sensors and recording gadgets to constantly collect data about themselves will lead to better choices about their health and behavior.

Companies such as Healthrageous are now testing whether self-tracking—for health or other reasons—can be sold as a larger-scale social experience to employers or the general public. And as with Facebook, says Healthrageous CEO and cofounder Rick Lee, data collected about user behavior may be "the most valuable asset in the company."

"When you start to do large data crunches with different variables and human characteristics, you get some interesting data that would be fascinating in the hands of pharmaceutical researchers looking to develop new drugs," he says.

It's not yet clear how big a business self-quantification will turn out to be. Nike tapped into a large market with its wireless pedometers (which relay data from a running shoe to an iPod); many other firms are attempting to build communities through games or free apps to track health problems, although most still have relatively few users.

"Anyone who can code software can write a self-quantification app; the question is who can move the world and change business with it," says Paul Wicks, head of research and development for PatientsLikeMe, a site where 115,000 patients with serious illnesses now track their symptoms and medications.

Healthrageous grew out of a 2008 study by researchers at the Center for Connected Health, a division of Partners HealthCare, that focused on people with hypertension who worked for the computing company EMC. These employees were asked to keep track of their blood pressure at home, and participants got feedback on their progress. The program proved so successful at lowering blood pressure that an independent reviewer estimated a three-to-one financial return, predicting that some EMC staffers would avoid heart attacks and strokes as a result of feedback they received.

On the basis of that success, the center's director, Joseph Kvedar, decided to commercialize the technology. It consists of an interactive software platform that collects data from wireless health-tracking sensors such as pedometers and glucose monitors. The information is uploaded to Healthrageous's website, where it is then analyzed and returned to the user via smart phone within a few seconds.