Lucylee: I'd argue he doesn't feel worse after this hospital stay than before it. Things were so bad, he agreed to go to the hospital. He isn't agreeing now so he must not feel as bad.
Harmony Well, that is the question, who are they selling the data to? First: yes, insurance companies. Secondly advertisers. They know our age, sex, etc from our sign in so they can take all the 43 year old women and produce reports on what they have in common and then sell the data to advertisers looking for information on cohorts. From the website cookies, they know what other websites interest me. From my link to MyFitnessPal they know what food I'm eating. My weight is in the system as well. They have a ton of information so can create pretty accurate profiles from the grouped data. There isn't a lot of proof that they are doing anything but selling more things to their own users (in other words, the advertisers are buying space on the fitbit website to advertise to me. Certainly my sleep data they are willing to sell back to me includes how other women my age and fitness level are sleeping (as if sleep is some sort of competition.)
In theory they will never sell INDIVIDUAL data to advertisers or insurers but we know that this data has been used in court cases and in some cases insurers are offering different pricing to people who fit different fitness profiles and you prove you are moving as much as you say through your trackers reports.
And the individual data has been used in court cases. Convicted one woman (she claimed she was raped in the night but in fact she had staged the scene herself and her tracker information showed her moving around for hours she claimed to be asleep - she smashed her fitbit, pretending it was broken in the attack but failed to understand the data was not on it, but on the server.) Another person won a claim for lost of quality of life suit. Her data showed how active she had been before an accident and how she was no longer active due to her injuries. It quantified the before/after fitness level and probably increased her settlement because it was based on hard evidence, not a vague perception "I used to be active and now I'm not."
I looked it up and currently data sales count for only about 1% of the revenue of fitbit. Another 10% comes from corporate deals (companies have an opportunity to encourage their employees to be more active which has been shown to have positive health benefits -- potentially resulting in lower healthcare costs for the company.)