There is a very interesting article on Business, Business 2.0. The Technology of the Year: Social Network Applications
Social networking applies the power of the network to one of the most fundamental problems in all of business: finding the person who has the critical information you need, right when you need it.
There are all the cool companies playing the game: SixDegrees, Spoke, VisiblePath, Friendster, RyzeIn, ZeroDegrees. There is a mention about CIA interested in using these ideas and the article finishes with an important concern about privacy.