Mastodon
Official
Website: joinmastodon
Official instances: mastodon.social
mastodon.online
List of instances: joinmastodon/communities
Forum: discourse joinmastodon
What does Mastodon feel like?
What are some advantages over Twitter?
What are some limitations?
What are Mastodon forks and why use them?
External Links
Guides
What is Mastodon (video)
Getting started with Mastodon
Guide to Mastodon
Mastodon: Friendly Microblogging