I'm seeing random posts from people i don't follow in "Local timeline." Does this change over time with the people I follow?

@MrHodl Local timeline is showing you all posts from your mastodon instance.

Your instance is @mastodon.social, so you see all the posts from people in @mastodon.social (like me)

Thanks for the answer guys.

Is there a way we can make our own "instance"?

@MrHodl Mastodon is open source and self hostable. you just need to own a server, a domain and get it set up.
See this link for details:
https://github.com/tootsuite/mastodon
tootsuite/mastodon

Your self-hosted, globally interconnected microblogging community - tootsuite/mastodon

@Strit @MrHodl Making an instance is more for someone who want to host a community, but I guess it's possible to create one for you and your friends
@caillou @Strit Can't we all make an instance have it connected to all the other Instances on the network?
@MrHodl Sure. It would work, but it would be a waste of ressources. Not everybody needs an instance.
@Strit What are the benefits of hosting yourself? Censorship resistance?