Transformative Works and Cultures

However, this customization extends only to people, not to topics.
No mechanism for filtering posts on a given topic exists.

But you can follow a particular tag and turn your message inbox into a filtered reading list. I follow some writers that way, usually if the tags I'm interested in are rare compared to their usual topics. Course it only works if they tag consistently.

I was all *nods* about the rest of your points.