As a quick start in the early evening here are some #activitypub links
Official forum where we meet
Official site (better soon)
Our last conference
You can also join the W3C Social CG and mumble with us in regular meetings https://www.w3.org/wiki/SocialCG
Server run by the main developers of the project It is not focused on any particular niche interest - everyone is welcome as long as you follow our code of conduct!