I made a flow chart of which Mastodon posts end up in which timelines!
So, you can see how each instance will have a different local timeline, and even a slightly different federated timeline - and you can see why the federated timeline moves so much faster than the local one, too.
Full disclosure, this diagram is not complete. For example:
- If someone followed by someone on your instance replies to a public toot, that public toot will end up in your federated timeline.
- If someone on your instance follows someone who boosted Foo's public toot, Foo's public toot will end up in your federated timeline.
... but I didn't want to make the diagram too 🙃 , you know?