What habit trackers collect, and what they do with it
Sleep, mood, exercise, location and a daily timestamp. It is a richer profile than most people realise.
A habit tracker sees an unusually complete picture of a person. Not just what you are trying to do, but when you do it, when you stop, which days you fall apart, how much you drink, whether you slept, and how that changed over two years. Combined with a timestamp and an approximate location it is a better behavioural profile than most apps that are explicitly in the profiling business.
Most trackers are not doing anything sinister with it. Plenty are doing something careless, which in practice can end up in the same place: analytics SDKs that ship event names containing habit titles, crash reporters that capture a screen with your list on it, a cloud backup with no encryption at rest, and a privacy policy that reserves the right to change later.
The App Store privacy label helps, but it is self reported and it describes categories rather than specifics. “Health and fitness data, not linked to you” can be true and still mean your habit names are on a server in a table with a stable device identifier next to them.
This page covers what these apps typically collect, how to check what a given app actually sends, what the privacy label does and does not promise, the questions worth asking before you commit two years of logs, and what miniHabits collects, which is a short section.
Outline
Status: outline. The introduction above is finished copy. Everything below is the section plan for the full draft, targeted at about 1 900 words.
- What the data reveals. Building a profile from a year of habit logs, as an exercise.
- Typical collection. Analytics, crash reporting, backups and the accidental leaks.
- Reading the privacy label. What the categories mean, and what they leave out.
- Checking what an app sends. Two methods, one of which needs no tools.
- Questions before you commit. Five, answerable from the App Store page and the policy.
- Policies that reserve the right to change. The clause to look for, and what it means in an acquisition.
- What miniHabits collects. The short version, with the sync design linked.