Value in Social Networks

Since I posted my social network map, spent some time working on two things. The first thing I did was try to figure out how the multiple posts to a couple of sites were happening. This mostly affects Facebook, but also affects FriendFeed and Storytlr. From looking at the map in the earlier post, it seems kind of obvious that the issue is the number of feeds I have that all go flow to the same sites. And it seems that the obvious answer is that some of the branches that make up the tangle of social networking sites need to be pruned. And even some sites removed completely. Even I was a little surprised to find that I had interconnected about 20 different sites. But which branches, connections and sites to prune?

This is where the second thing I've been trying to work on comes in.

I have been trying to figure out if there is any way to decide how to prune the tangle based on the value of the various sites, connections and networks.  This does beg the question of how does one actually determine the value of a social social networking site.

Value is one of those words that are really hard to define.  What exactly is the value of a social networking site?  There are lots of things I actually don't like about a number of social networking sites, but that really is another post.

This post is ultimately about how I figure out how to scratch a personal itch and get rid of duplicate updates going to multiple sites.  Cause I really don't like when that happens.  I find it annoying.
There are 19 sites I have been using.  It is really a higher number than I originally expected.  There are a lot more sites out there that I either haven't looked at or didn't find anything "different" enough to use.
As to the question of value, I still don't entirely know.  What value does a somewhat antisocial person derive from social networking tools? 
Looking at the data I have collected here, I can think of three primary metrics: number of sites using that site as the source of a feed, number of friends/followers/whatever I have at that site and the number of links from that site to SysMango.com that I don't think are me just following my own links.
And that really leaves two, because SysMango.com has been dead recently.  And I wasn't able to find more than 4 referrers, and all those were from Facebook.
From here, I can start looking at the various sites and may say something about the value I get from them, or how I use them, or why I bother.