Let the community detail (community settings... aka metadata) which TAGS they'd like to use to subdivide posts.
Not sure how well hivemind handles this but i'm guessing it will be just fine.
This provides pretty much ONLY a subdivisions of content but also does kind of let users know which kinds of content is popular and expected.
I think what I would prefer this as a basic option. This is basically what I was suggesting above, but I forgot to add that part, that the community owner dictates what sub-communities exist. I imagine it being an organic thing that once a certain portion of the community gets big enough, they can break off and form their own -sub-community.
I think that with the option to be able to have community mergers which sounds like what you were talking about in option two could be an advanced option that I could see being useful if two communities independently grow but have large intersections in their communities they could merge under a parent community, but also maintain their independence. THAT sounds really powerful especially combining that with smt's and the monetization of communities.
So sub-dividion of content and yet also have sub-communities?
I thought we were talking about the same thing with those. What do you mean when you say sub-division of content?