Many have been overwhelmed by the amount of information in the spec, to the point some have written guides on how to read it that begin with stating what you can safely ignore. That is only the tip of the iceberg, as the whole introduction to ActivityPub could be potentially rethought - this forum being a prime improvement at organizing the information.
I suggest splitting the discussion in work packages centered around the learning steps involved:
- understanding what problems ActivityPub solves/doesn’t solve
- understanding what technologies ActivityPub uses
- understanding the untold:
- what is generally not implemented and why
- what are the common deviations to the spec (a.k.a. dialects) and how to be compatible with them
- what other technologies play a major role in most implementations (Webfinger, Signatures, etc.)
- what is a minimal implementation for each functional block of the spec
- what are the tools that could help in that development, if any
- libraries? good examples in major projects?
- having feedback:
- where to ask questions
- where to check for compatibility (reports? test suite? forum?)
- giving feedback:
- where to declare deviations to the spec and explain how to be compatible with them
This is a rough list. Maybe we want to put our focus on some key points, but we should also pay extra care on how we cary the developer along that process, beginning with where that information is first given: probably http://activitypub.rocks/. What part of the explaining/dispatching belongs to the landing page, and what belongs to the forum is up for debate.