This dissertations presents an algorithm on the webgraph for finding dense bipartite graphs wich represents web-communities.
By performing further steps of the algorithm several levels of communities are recognized which can be related to communites of former levels.
The web can be represented by a graph with special regions: SCC, IN, OUT and TENDRILS.
Regions are defined by the link-path-reach from one website to others.
The linkage to and from a website (in- and out-degree) seems to conform the power law, which is also mentioned in this document.
A. Schenker, H. Bunke, M. Last, and A. Kandel. Document Analysis Systems, volume 3163 of Lecture Notes in Computer Science, page 401-412. Springer, (2004)