We basically just track how people are using the plugin in order to know what we need to improve or streamline. For example, how many people are using compatibility mode versus having custom template overrides, how many people are using the new API’s or using the help page, how many books the average user has and how long they use the plugin. We also have some A/B tests measuring different ways we can improve our UI. We don’t track any specific data about your books or anything that is not strictly anonymous.
Currently there is just the one admin notification asking users to allow or disallow tracking because we thought that would be sufficient for most people, but we can add it in if we have reports of people accidentally enabling tracking and wanting to disable it.