If I go to one website, for example Reddit, and post a text or image, what information of me will be stored in their database and will they ever delete this information in the future?
What I can think of: timestamp of the post, IP address
anything else?
Check their privacy policy and terms of service. Also they could always lie in both of these. You will always have to trust them.
Upon lying, I’m sure you could whip up a class action law suit, but I’d expect this to not be the norm.