I'm fascinated with the power of networks. Visually they are complex and almost overwhelming. They are really just about relationships - how point A is related to point B .... and so on. I remember Don Siekmann (Managing Tax Partner Arthur Andersen Cincinnati) saying "Your network is your most important asset".
I used that line in most of my annual reviews of staff at Accenture. I would pull out my palm pilot and go to the statistics page saying to my staff - how many people are in your palm pilot? Or pull out your Rolodex file c(you technology dinosaurs) and count the number of business cards.
There are people who I call "Network magnets". Those are the people who have network diagrams (professional networks, social networks, spiritual networks, family networks etc.) that would make your head spin. When you need to "network" they are great "go to" people.
The challenge is how to maintain a network, once created. Should you be deliberate - or random? I don't lose much sleep over this issue. I let the network take care of itself.