Great post by James Governor at RedMonk about something I’ve been thinking about for a while now — the idea that everyone’s Twitter feed is a unique view on the world, that you can’t always see every conversation that everyone else is having. He calls it “Asymmetric Follow,” which is as good a name as any. It has really different scaling characteristics than a lot of online communications we have, and is fascinating to me lately. (I’ve found myself following @reply threads of other people into various subcultures and piecing together relationships sometimes — of late those of The Daily Show writers, who are a little, um, quirky.)
Asymmetric Follow
John's Blog 
Asymmetric Follow is one of the things that makes Twitter work so well. Assuming that two people are equally interesting to each other is a very dangerous assumption.