"As was shown by Kumar et al. the web contains many densely connected directed bipartite subgraphs because cyber-communities often have such a dense connected structure. The source nodes in such a subgraph are the 'hubs' or directory nodes on the topic; the sink nodes are the 'authorities' or content nodes on the topic. Kumar et al. also presented and implemented an algorithm to find small complete bipartite subgraphs, which they call cores."
She references a paper by Kumer et al., 99, "Trawling the web for emerging cyber-communities".
This relates to my interests in searching and partitioning the blogsphere.
For an introduction to the structure behind the web read: Linked: The New Science of Networks.
