Robert Scoble talks about the problem with social networking and also provides a link to the CNET.com article Five reasons social networking doesn’t work.

There was so much of buzz and hype about Social Networking in the last couple of years. My take on this issue.

Social networking is a really cool concept and it works great if used
right. In a nutshell, Social networking is the technology
implementation of “six degrees of separation.” You can reach anyone
else in the world in six hops. While this may be true, trying to
exactly replicate it and think that it will work may be asking for too
much. Let me explain. Take a look below

                         
1 – 2 – 3 – 4 – 5 – 6

Let’s say #2 wants to reach #6 and the introduction request reaches #4.
It’s a tricky situation for #4 as neither he knows #2 directly nor he
knows #6 directly. But the request came from someone he knows very
well. My take in this scenario – most of the times, the request will
stall and won’t move. It will also put a strain on the relationship
between #3 and #4.

One simple way to overcome this is to create a rule that you will only
connect people who are directly connected to you. For instance, if #3
wants to connect with #5 and the request comes along to #4, it should
be a “no brainer”

I think the jury is still out on this. More on this a few days later.