My baseless opinion is that having a variety of instances with varying ethoses means that there’s a good home instance for everyone (not just the verysmart, young, white, male, liberal a la Reddit), and federation means that that variety of people are intersecting and interacting a lot more than if instances were completely separate. At the same time, it still feels like a small community, or maybe a bunch of small communities. There seems to be a lot less of the snarky clapbacks and unpopular opinions getting nuked that’s typical of other social media.