Well, I know in Lemmy you end up with many communities on the same subject but some clients let the user join communities under a single banner, which is somewhat helpful but I don’t think that’s the ultimate answer for the most part. It does seem like communities win out based on number of users, but you always end up with somebody that doesn’t pay attention to that number and participates in the community with a few users. I do think Lemmy is a good test testing ground for figuring out what works.