[rantanplan]

Kindles have a reading statistics page, that actually takes all registered devices into account, even if you're using the android app. I've never tried this before, but if you sideload a book via Calibre, do the reading statistics also work with these books and are they persistent after you delete the books?

I'm asking because on Kobo, the statistics don't seem to sync between devices and also they don't stick if you delete a sideloaded book.

I know that these are vanity metrics but I always liked this aspect, that you can potentially look into a calendar and see on which days you read and how much. Unfortunately, there isn't a service/API that would take all statistics from all kind of devices and enable you to create reports on your reading habits.