Twitter became a thing in our college town around 2009. Back then, I could count everyone in my town who was on Twitter with my fingers and toes. It's interesting that one of the first things we did, beyond settling on our hashtag was a organizing an in-person tweetup at a coffee shop. It was such a great way to meet different people in your community.
I'm curious if Mastodon could be a neighborhood level social network. Not like Nextdoor, but owned and managed by a neighborhood co-op?