Often times people ask me, "But how do I learn about how ActivityPub works? Where do I get started?"

Friends! The ActivityPub spec itself is here to help you! There's a really lovely story-driven tutorial about ActivityPub right at the top of the spec in the "Overview" section! https://www.w3.org/TR/activitypub/#Overview

Give it a read! I tried really hard to make it easy to follow, and it has beautiful illustrations from @mray!