@thomasfuchs For transitive relations between servers you have 3 options:
1) Eager loading: You replicate and cache lots of posts, server admins complaining about storage.
2) Lazy loading: You load the posts on click, it takes time, users complaining about UI/UX.
3) No loading: Just a subset of posts gets loaded, admins are happy and users complaining about missing posts.
Current solution: You open the thread on the original server.
Needless to say, we have lots of room to improve. 🙂