I'm often grumpy about how "loose" the #ActivityPub protocol is. So it's important that I also point to positive examples of how to do it well.
https://w3id.org/fep/b2b8: "Long-form Text" is a great set of concrete terms and concepts that moves the #Fediverse forward in some really good ways. As we continue growing beyond "microblogging" we need this, and more stuff like it.
Thank you to @evanprodromou for putting your time into this document. It's a solid investment for everyone.