A Federation of Communities built on Posts
A post is a container of content.
A post starts with a manager/editor, who can edit the content of the post, and more importantly, specify privileges related to the post, such as who can see it, who can read it, who can edit it.
A post can have sub-posts. These sub-posts have their own manager and settings. Sub-posts can have their own sub-posts. Manager of parent post has no direct control over the sub-posts, but they can choose the order of sub-posts, and to “expel” the sub-posts. Managers of sub-posts can also re-attach their sub-post to another post, given the manager of the new parent post agrees to it.
If a parent post is deleted, the children posts will remain. They just cannot be accessed from their parent post.
A post has a unique and permanent URL, and my have mutable alias URLs. When visited, the reader only sees a root post and its direct sub-posts.
Image a reddit, except everyone (invited) and create channels (posts), and they can freely choose to associate with other can create a mega-channel to contain their containers. Or if they get dissatisfied with the policy of the parent channel, they can move away. The same way founding states of US freely chose to form a federation, while retaining maximal control over their own territory.