I helped the Bluesky team write a paper explaining the underlying architecture and the reasons why it works the way it does. Releasing the paper today to celebrate that you no longer need an invite code to sign up for a Bluesky account: https://arxiv.org/abs/2402.03239
@pettter That's correct – all posts in Bluesky are public (you can choose to hide them from logged-out web interface users, but they are still available to logged-in users and via the API). Blocking someone can never totally stop them from reading your posts because they could just log in to a different account to read your posts.