Some food for thought:
Social networking “fatigue”, from 11/2/2006
The emergence of an older generation of users, from 8/20/2007
Survey numbers on the impact of social networking applications, from 4/12/2008
A more personal story, from 3/15/2009

Shouldn’t a significant enhancement be made to allow different strata of friends? The idea is that you have that inner circle that should be unfiltered and broad, and then groups that extend outward but allow you to control the level and messages at a finer level. There are political correctness issues here, of course: what happens when someone finds out that you’ve put them in the “not-so-close” group? What if you update one group accidentally with information that you didn’t mean to disseminate? What if a friend stops being such a close friend and you decide to move them to another group?

Does the functionality benefit outweigh the political risks and social downsides? Recommendation: Allowing people to have better control of their network would likely drive the adoption of a single social networking platform as a destination. At the same time, this sort of functionality would also likely encourage the dissemination of even more information, thereby increasing the value of the platform as an investment. I think that the first platform to do this will have an almost-win-win on their hands, but they’ll have to be very: 1. brave, 2. savvy about pitching this functionality, 3. gradual about monetizing this capability.