Exactly this. I like how substack works and have no idea if it’s doable or not.

Hashtags could possibly help with this. When making a post, a user can add hashtags which categorize the content. One can then search hashtags, or subscribe to them to find new communities. Probably not as passive as you’d be looking for, though.

Recommendation algorithms are a big reason for the enshitification of other social media. You don’t need to be connected to everything everywhere all at once. Enjoy your handful of small communities.

Problem here is also that your instance may not know about all communities from the instances you’re connected to. This could probably also be improved.

I guess the ‘simple’ way of doing this would be adding tags to communities like ‘art’ ‘hobbies’ ‘sport’ ‘football’ etc. This might then let the app suggest others based on the tags you are subscribed to.

It would probably still require some AI/analytics to work out the links based on user activity in different communities/tags but I think it would make it easier to group interests and promote smaller communities.

It could also improve Lemmy visibility in Masterdon if the tags are used as hashtags or something. (Would require more work)