When tracking your period lets companies track you (npr.org)

Health apps can be a great way to stay on top of your health. They let users keep track of things like their exercise, mental health, menstrual cycles — even the quality of their skin.

But health researchers Giulia De Togni and Andrea Ford have found that many of these health apps also have a dark side — selling your most personal data to third parties like advertisers, insurers and tech companies. Their research makes clear that surveillance capitalism is here. You are the commodity.

See https://text.npr.org/1068930998 and https://news.ycombinator.com/item?id=29989781