Users should be able to have multiple possibly named feeds with per feed sharing policies (Public/Following/Accepted Follower).
A default sharing option: Public/Following/Accepted Follow/Named Feed(s)
When sharing a post the user is set to the default sharing option, and can change and/or publish to multiple of his her feeds.
Motivation: Many social streams suffer from mixing private, serious, professional, and hobby related, etc. posts. Sometimes that is good, but often i am only interested in certain kinds of posts by a person. Multiple shared feeds would allow users to channel their posts if they wish to, i suppose it might also increase the number shares (and this make the plattform more attractive) e.g. if I like to maintain a public feed i might be reluctant to share some posts even though i know some followers would be interested. No more complexity by default, but more options for power users.
After all the intelligence filter seems to solve exactly this from the subcribers side of view