@blaine @cwebber I have a question for both of you while I have your ear.
It's about RSS 2.0!
One thing about ActivityPub that makes it hard to implement is that we don't have an explicit description of how a polling mode would work. I started one here: https://w3id.org/fep/b06c
I think it may make sense to describe how RSS 2.0 could fit in the picture, too. Having a defined mapping for RSS items into AS2, defining how IDs and uniqueness can be treated, and so on.