Absolutely one of the best organizational methods I have seen in a while Density is huge. Usability is amazingly good. Also content is amazing with great links behind it.
For an upcoming documentary by Benedikt Bjarnason, RhNav - Rhizome Navigation was used to create animated visualizations of large genealogy data sets...
p2pfoundation has an interesting post about the importance of time as a dimension in social networking technology. My concept of RhNav - RhizomeNavigation includes some of these thoughts...
I. Cadez, D. Heckerman, C. Meek, P. Smyth, and S. White. Proceedings of the Sixth ACM SIGKDD International Conference on Knowledge Discovery and Data Mining, page 280--284. New York, NY, USA, ACM, (2000)