A few years ago I made this 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.
This is why it's important to boost good posts and use hashtags - the fediverse is fragmented and harder to search by nature.
@cassolotl Hi, thanks for the great flowchart, it does a great job clarifying the mechanisms. I wish I had seen this when I first came here 
Also, has anyone offered to translate the diagram into different languages? I would love to translate the graph and alt text into Simplified Chinese and send those to you, if you’re interested.
@cassolotl Hi, just wanted to tell you that I posted a toot translating your original toot, including the flowchart and it’s alt text. https://weirder.earth/@unperson/108321140439934807
Thanks again for making the Fediverse a safer and better place. 
@unperson Thank you for letting me know! :D It's great, thank you for making it accessible to more people!
@cassolotl Aww thank you. I love how clear and informative your flowchart is and I hope it gets included in the official docs somehow.
@cassolotl Thank you for the generosity. Then I'll post it later and credit you as the original author.