The Enronic gets my vote as best social network analysis tool ever (both system and instance. This should have great potential as a tool for consultants and researchers, provided you can deal with the privacy issues. I especially like the idea of introducing animation – imagine introducing changes into the organization, and then watching the emails fly in real time…
(Via BoingBoing)
Applied Abstractions
Espen Andersen's take on technology, strategy, and many other things
Applied Abstractions 
I saw something somewhat similar with the focus of analyzing the blogosphere as a social network from a bottom up approach, leaving of course from the concept of a densely inter-connected conversation. The pdf can be downloaded from http://www.blogninja.com/hicss05.blogconv.pdf
Thanks for the tip – this type of analysis is coming into its own, going from concept to more available application.