But does it say what Followers / Following means? What if I have completely different custom actor types..
Tim Berners-Lee's Semantic Web failed because there was they idea to have universal semantics that applied globally.
It is very important to have closed vocabularies, imho, where the terminology only have well-defined meaning in a specific domain.
This matches the idea of domain-driven design (DDD) where you have bounded contexts.
@humanetech @sl007 You would technically follow the spec if you have these collections, return them as always empty, and send Reject{Follow} for any Follow you receive.