What, semantically, allows me to identify an actor? If they can be things other than AP Actors or whatever, what do I use to identify the fact that I can "follow" the object? Why is it a feature that this information is not encoded into the type field?
What does it mean to follow a Note? What would I expect the behavior to be from that? How should I be expected to interact with the followed Note? What happens when a Note follows me?
Who defines and controls the Note's permission model?