ActivityPub

Appendix A. Activity Vocabulary Types

Each object type in this appendix has the following information:

Information	Explanation
Extends	Any other type it extends (if any).
Group	Rough grouping, not necessarily reflected by the type hierarchy.
Importance	The relevance of this type for most developers: high, medium, or low.
Notes	Notes on what the type is used for.
Properties	The most relevant properties for this type.
To publish	Notes for publishers to maximize interoperability.
To consume	Notes for consumers to get the best behavior.
See also	Related types from the Activity Vocabulary and equivalent types from other vocabularies, if any. These might be useful places to search for properties that might be missing with this type.

A lot of this information is my subjective opinion. I have a few biases: I want to see maximum interoperability between ActivityPub and AS2 implementers, and I want to see more implementations of cool applications on top of ActivityPub. If those aren’t your priorities, my opinions might not make sense to you. Caveat emptor!

I’m also one of the editors of the Activity Vocabulary spec, which is considerably more terse and general about most of these types. Whether we should have more specific, more elaborate descriptions in the AS2 specifications is an open question, but you should get a pretty detailed description here.

As you may remember from Chapter 2, Postel’s law for interoperability, by the internet’s great standardizer, ...