We have known that the connection to each other is just a six degree of separation. To put this to the test, we could go make use of our MSN contacts and view our friend's contacts list and start tracing down. If it is possible to make a software using MSN Contacts web service APIs to automate this function of mapping the "friends-of-friends", we would be able to some how see a huge portion of the world linked to each other.
For agencies who love to peek at our private lives, they could use this technique and have already been using this technique to map our relations with others.
This also expose a fundamental social security problem which is to allow people to freely access your friends and contacts list without the proper security measures to restrict views. Even if you restrict the view on your own list, people could use the concept of "six degrees of separation" to find others who have YOU and make a map about who have YOU in their contacts list, making it difficult for you to hide yourself.
So what's this all about. This is the prove that our social privacy, is faulty and weak even with access restrictions, are we able to fully hide our private life from others and protect it ? Yes to a certain degree as long as others do not have any "pointers" pointing at you.
Does it mean that we should just stop all privacy controls and just open up our life for all to see... making ourselves "naked" in front of the world ?
No. It means we need a far better measure to protect our private life and anonymity then what we have currently.