I think it helps if one is given the option of segregating individuals, or groups of people, into what I've coined a VoxBox - containers that show comments, posts, or any general stream, in discrete streams, per person, but on the same page or screen with others. People can be grouped by my Personas: personal, professional, familial, platonic, erotic, romantic, UnPeople, etc.
Here's a quick mockup of an interface design for a lifestream of twitter tweets. One is horizontally oriented and the other is vertically. People who aren't inter@cting (typing with @username ) and just announcing don't have to be segregrated into their own 'voxbox' and can be lumped together like the current interface (a "background chatter" box). Affinity and reputation scales can sort and group followers and fans into clumps.