I've been looking for a free Reddit alternative and preferably one that was federated. I'm not really sure how federation works with this though. A lot of similar sites are just personal projects that people made as a hobby that lack a lot of important features or the interface was really ugly.
I haven't seen how to moderate communities though but the Github page says this can be done, which I consider important since I want moderation to be done by communities and users rather then admins. If there's a quarantine feature similar to Reddit that would be useful too so I don't just have to ban communities.
Federation is critical to the development of alternative social networks. The reason people use specific social networks is because other people are on them. If there's an open source social network app that isn't federated, then everyone using sites powered by that app is isolated. With federation, all instances of the social network can interact with each other. Different instances can pop in and out of existence and the ones that stick around can become popular.
It's better for new social networks to be federated then isolated.