It's actually kind of uncanny to see the similarity between the disappearance of third places in the US, and the development of social media on the internet.
We used to have online third places - community-run spaces with some common interest in a topic, be it a TV show, a game, a hobby. Every space was its own thing, and the identifying characteristic was the community that built it. Forums are the most well-known example. You came there for the people, first and foremost, the topic was just the gateway.
Now we have social media that are entirely focused around the individual and their opinions and clout. And the community spaces that do still exist, are usually more like shopping malls - singular canonical subreddits that are sanctioned by the IP holder, controlled by them directly or indirectly, and expected to hold every single fan of the 'property'. No true mutual community, just a bunch of people in a room with a shared interest.
It's also in this context that I do not really see fedi as a long-term solution to social interaction online.
Sure, it is clearly better than centralized corporate platforms in terms of its ability to support community. But at its foundation, it is *still* about the individual, not about providing the tools for building deliberate community. And the entire federation setup is designed around that, too, it's not just Mastodon.
We can do better than that.
Tangentially, I suspect that this focus on the individual also provides an indirect advantage to whiteness (and privilege more broadly) and the structures that keep it in power.
Individualist systems always disproportionately benefit those who wield power, after all - those who are preferentially listened to, have the most to gain from a system that centers around clout and mythical personalities.