This is an interesting discussion by those who want to understand and improve social media. As I understand the position of the guest on this podcast, two things are important for improving social media. First, we need more options with focused agenda rather than big sites that confuse many different purposes. Second, the smaller, more focused sites require more obvious norms, rules, and moderation supported by onboarding for new members so they understand this guidance.
The guest describes his research with gobo.social (which does not seem to be up at the time I wrote this post. Maybe later.)