Pretty interesting.
I'm thinking about an #hackers organisations (or at least a rediscover of true #hacker #culture after the #profit centric mess that come out of the #SiliconValley).
Btw, maybe I'm missing something but your description of #ActivityPub remind me strongly #SMTP and POP, just over HTTP... and with mostly public emails.
Can you direct me to a good resource to understand the difference?