Ask HN: What are good resources for understanding data privacy as server admin

The situation is this: I created (creating) and own a web service and have complete (and exclusive) access to the data and code.

Obviously, people who use this service input data which is saved. I have access to the data as the owner and maintainer of the web app, and the user has access to their own data.

Ethically speaking, what rights do I have over the data (I assume few to none)? And legally speaking, what rights do I have over the data?

I know this is not a small topic, so I was wondering what resources you guys could recommend to better understand the scope and intricacies of this.

Thanks