Neat piece by Steven Johnson in the April 2003 issue of Discover.  Talks about two types of networks - the self-organising and social 'karass' and the more bureaucratic 'granfalloons', drawing examples from personal and corporate life. He goes on to describe the role of emerging social mapping software in detecting and mapping social networks - at the workplace in large organisations and in book-buying patterns at Amazon.    Some excerpts :

"Karass is that group of friends from college who have helped one another's careers in a hundred subtle ways over the years; the granfalloon is the marketing department at your firm, where everyone has a meticulously defined place on the org chart but nothing ever gets done. When you find yourself in a karass, it's an intuitive, unplanned experience. Getting into a granfalloon, on the other hand, usually involves showing two forms of ID."

"If these visualizations are interesting for individuals, they're even more interesting for large organizations, where social networks can play a key role in the success or failure of the operation without any individual really knowing where all the networks are. Every large organization has its granfalloons and its karasses. You have your executive vice president for sales, and the 10 deputies who report to her— that's a granfalloon. The karass is the group of 10 people from 10 different divisions who come together to make sure the new product ships on time. Granfalloons are what you see in the annual report and the business plan; the karass is what actually happens on the ground, when things are going well. It's that implicit social structure that both Donath and Krebs are after, in their different ways."

"tools designed to detect social networks are just as good at detecting antisocial behavior as well— for sniffing out the karasses that don't ever speak to each other or those linked by one solitary thread. For corporate managers and sociologists alike, this may prove to be the software's most useful function. It shows us the gaps in the network, the borders that no one dares cross."