If Basis can get its wristwatch/heart rate monitor to market, it will presumably make money from sales. But Chang is hoping for big money from a different place: selling an app that aggregates the monitor's data and analyzes it for you, the user.
"People aren't really interested in raw data," he says. "If I just gave you your heart rate data, you wouldn't know how to interpret it. In fact it might confuse you, or it might scare you and say, 'What is the spike? Why is it low; why is it high?'"
Facebook and Google sell advertisers the ability to connect advertising content to users based on extensive profiling information. In a similar vein, Chang's first self-tracking investment, Lumos Labs, has hundreds of thousands of subscribers paying for data on themselves -- and a paid user base that's more than doubled every year since they started sales in 2007.
"The beauty of subscription business models, if you can retain your users, is they can be naturally very profitable," Chang says.
But big data raises big privacy issues.
Two years ago, some users of a leading self-tracking brand, FitBit, were logging their sexual activity as exercise. Then their sex logs somehow popped up on Google searches.
Woody Scal, FitBit's Chief Revenue Officer, says the company has made privacy settings more prominent, "so that people are more aware of what the privacy settings are. I think the area of privacy is an area that many companies like ours have learned a lot over the past couple of years."
FitBit is entering a brave new world in privacy as they start selling devices and data to a new market: employers. Scal says FitBit is attempting to grow through corporate wellness programs.
“Companies can see how many of the devices they’ve given out have actually been activated," he says. "How many are being used? How is it actually changing employee behavior?”
Scal explains bosses don't get reports on an individual employee. They get aggregated data, and the worker must consent first.
One of FitBit's competitors, BodyMedia, says it's working with insurance companies to get its self-trackers into more workplaces. Scal says FitBit is running an experiment with one insurer, to see if employees who use the devices go to the doctor less, something he describes as the "Holy Grail" for self-tracking products. "If we could make a direct connection to reduction in medical care costs, then I think the floodgates would be open," Scal enthuses.
Consent to What?
But Marc Goodman, Chair of Policy, Law and Ethics at the technology research hub Singularity University, sees a big risk. "People should be asking themselves, 'What happens with this data? What type of inferences can be drawn from this data?'"
He says users typically don't read disclosures. And while health and fitness devices are personal tools for now, Goodman warns, health insurers in the future could use incentives to pressure people to wear these devices."So that they could get a better perspective on how healthy or unhealthy you are," he explains. "If your self-tracking health device shows that you lead a sedentary lifestyle, then maybe you will pay more for insurance."
Goodman says consumers should be careful about letting any company track health data that can be used against them.
An earlier version of this story stated that Facebook and Google sell hyper-personal information to advertisers. That is incorrect. Facebook and Google sell advertisers the ability to connect advertising content to users based on extensive profiling information. KQED regrets the error.
Listen to Aarti Shahani's story: