Publics
Flow
Phatic
Tummeling
Out-groups
Faces
Following
Small World
Networks
Minimal group paradigm
Democratization
Stimulation
Homophily
Power
Mutual Media
Csikszentmihalyi
danah boyd
Kevin Marks

VP web services, BT
The idea is that you're living inside the stream: adding to it, consuming it, redirecting it. The stream metaphor is about reaching flow.
Parasocial
Semi-overlapping
[teens'] idea of public is not about all people across all space and all time. They want publics of peers, not publics where creeps and parents lurk. 
danah boyd
I would guess that the typical profile of a ‘follower’ is someone who is young and who feels marginalised, empty and pointless. They don’t have an inner life. 

 http://bit.ly/james_twitter

Oliver James, The Times
if you’re on MySpace now, you’re a [expletive] cretin. And you’re not only a [expletive] cretin, but you’re poor. Nobody who has beyond an 8th grade level of education is on MySpace. It is for backwards people.
 
http://bit.ly/wolff_myspace
Michael Wolff, Business Week
Google Talk will also be integrated with the pages themselves making it super-easy for Orkut's Brazilian drug dealers to text message and voice chat with each other.
 
http://bit.ly/mash_orkut 
Pete Cashmore, Mashable
friendfeed.com
friendlierfeed.appspot.com
Yes, they have Orkut and OpenSocial, but no one actually uses them. Okay, some people use them, but not in the meaningful social ways that people use Facebook or even Twitter.
MG Siegler, TechCrunch
http://tcrn.ch/9LJx9m