I think Facebook has basically gotten the visibility of the hierarchy correct with their setup of friend lists. I assign my friends to different groups, but the

I think Facebook has basically gotten the visibility of the hierarchy correct with their setup of friend lists. I assign my friends to different groups, but they don't know what groups I've assigned them to. The biggest things FB needs to change in my opinion are to make it simpler to post updates to different groups (it's there now but it's clunky), and allow me to segregate access to my information by group. So for example I can set it up so that my college friends can see what my college friends write on my wall, but not what work friends write. I think there might also be some value in having a somewhat public hierarchy, like you initially mentioned, but I think that makes more sense on Twitter than FB. It'd be nice if Twitter let me have explicit topic-based channels for me to publish to, and for people to subscribe to. So I could subscribe to some people's programming related tweets without hearing about what they ate for breakfast.