HN is still my favorite social media site. All the best online communities I've kept up with since the 90's have been community-driven BBS derivatives attached to a centralized entity where the community discussion is only tangenially related to the hosting organization. A lot of them attracted people who didn't even engage with the host's content much at all. The hosting organization just acted more like a host at a good party, attracting the right kinds of people to connect with each other.

I think there's some kind of a Goldilocks zone that happens when the organization that hosts the social media site engages in good content moderation but doesn't try to heavy-handedly control the conversation according to its own goals, allowing the community to direct itself in a balanced way. This type of attitude could help the fediverse grow too.