i own them all and have tried each one on and off for the last couple of years. i like each one in its own way (and, also, am friends with guys at each place)
if you're just getting started and you aim to keep it light, then i'd start with the withings scale. you leave it in your bathroom, set your goals, step on it when you feel like it and watch trends and alerts from time to time. i find my weight tells me more about me over time than many other metrics: it shows my bad weeks from my good and, in indirect ways, shows when i stress out and get bad sleep (and therefore, end up eating poorly and exercising inconsistently)
this is why i believe a smart scale is one of the best examples of good data tracking: you step on it whenever you think of it (not on some weird schedule; nor do you have to wear it or take it with you). it does the mundane stuff of capturing the data and sending it to the cloud, which you would otherwise have to write into some notebook.
if it's a system that's fully automated though, one might lose interest in collecting it in the first place: the QSers always like to say – when you add a little friction to a process, you end up paying more attention to why it is. so instead of just blinding capturing your weight, setting up alerts for goals and seeing trends fall and rise will get you to make the most of the data – instead of just collecting data for data's sake.
you could probably do it today without the use of a private account
i believe in app settings, you can restrict the visibility of posts by any particular app. this way, your scale's posts could be seen by just you and not your friends.
you're totally right on all these points: for the time being, i've only put out information that's okay being 'public', but i imagine when you do want to share a set with a small group (let's say your physicians), you'll want an additional layer of access control.
couldn't one also keep track of the 'source' from where a data point comes (i do this, but don't reveal it in the API - yet)? this way, when it comes to discoverability via some algorithm, you could always separate the 'verified' bucket from the 'unknown' bucket?
yes, i do think of it that way: as we leave all this data exhaust behind us, i keep wanting a system to have it all in one place – or at least, an "interface" that shows it to me in one place, even if that's not how the backend really is.
thanks for the book recommendation - i will check it out this weekend!
if you're just getting started and you aim to keep it light, then i'd start with the withings scale. you leave it in your bathroom, set your goals, step on it when you feel like it and watch trends and alerts from time to time. i find my weight tells me more about me over time than many other metrics: it shows my bad weeks from my good and, in indirect ways, shows when i stress out and get bad sleep (and therefore, end up eating poorly and exercising inconsistently)