Wearing an activity tracker gives insurance companies the data they need to discriminate against people like you

Many insurers offer breaks to people who wear activity trackers that gather data on them; as Cathy "Mathbabe" O'Neil points out, the allegedly "anonymized' data-collection is trivial to re-identify (so this data might be used against you), and, more broadly, the real business model for this data isn't improving your health outcomes -- it's dividing the world into high-risk and low-risk people, so insurers can charge people more.

That means that if your fitbit-a-like shows that left-handed vegetarians like you are at higher risk for expensive medical treatments, then people like you will end up paying higher premiums -- and you'll have helped make that possible.

Think about what that means for insurance. It’s meant to be a mechanism to pool risk -- that is, to equalize the cost of protecting against unforeseen health problems. But once the big data departments of insurance companies have enough information -- including about online purchases and habits -- they can build a minute profile about each and every person’s current and future health. They can then steer "healthy" people to cheaper plans, while leaving people who have higher-risk profiles -- often due to circumstances beyond their control -- to pay increasingly unaffordable rates.

If we're not careful, pretty soon it’ll be almost like there's no insurance at all.

That Free Health Tracker Could Cost You
[Cathy O'Neil/Bloomberg]