@mikebroberts While the W3C specs exist as a reference, I wouldn't recommend starting there—they're underspecified and don't provide enough practical guidance for implementation.

Instead, I'd suggest these more practical resources:

1. Fedify's Creating your own federated microblog tutorial:

   • Provides a hands-on, step-by-step implementation
   • Covers both the theory and practice in an accessible way
   • Shows how to handle common ActivityPub patterns

2. For a better conceptual overview:

   • Sebastian Jambor's excellent Understanding ActivityPub series
   • Darius Kazemi's A highly opinionated guide to learning about ActivityPub

3. The SocialHub forum has many discussions about implementation practices and challenges faced by developers.

4. The FEP (Fediverse Enhancement Proposals) process documents community-developed extensions and conventions that go beyond the official spec.

The biggest challenge with ActivityPub isn't understanding the core concepts, but navigating all the de facto standards and practices that have evolved beyond the specs. Starting with practical tutorials rather than specs will give you a much clearer path forward.

@hongminhee Fantastic - thanks so much!