I think Jack is bringing up a really key point when he discusses positional value! A Network Weaver needs to be aware of where he or she is in their network(s). I often have individuals or groups of people from an organization or project take a large piece of paper and start drawing their network. In addition to including all the people they work with, they need to identify the connections between those individuals. They also need to include all of their friends' friends--people their friends have talked about but who the mapper does not really know.
All of this mapping helps people think about their position in the network. When someone comes to them with a dream, are they able to connect that individual to people who have the resources and ideas that will enable that person to turn the dream into reality?
Of course, a much more accurate and complete picture can be obtained by surveying the network and mapping the results, then looking at your individual scores for a range of metrics. But either way, you can start to improve your network position so that you can be a better Network Weaver.
For example, I've been trying to help a wonderful energetic candidate for mayor in our small town access information about what other small towns are doing to support Smart Growth--helping local businesses flourish and encouraging effective approaches to energy conservation. In my head, I started drawing a network map of my network that might provide some help in this arena. I realized that if I was going to be a true Network Weaver for him, I had to spruce up my Smart Growth network! I started calling up some people I had worked with years ago in economic development and quizzed them about their network. As I add these new folks to my network, I'm able to introduce the candidate to some truly effective Smart Growth wizards all around the country.