Aaron Clauset, Cristopher Moore and M.E.J. Newman published a paper in Nature about the automatic extraction of hierarchical structure of networks: Hierarchical structure and the prediction of missing links in networks. There’s a free PDF of the paper on Mark Newman’s personal website.
In the abstract the say that their
results suggest that hierarchy is a central organizing principle of complex networks, capable of offering insight into many network phenomena.
This is of interest of a pet project of mine that I haven’t spent much time on in recent years, but may again in the future.
I’m rummaging through my old bookmarks… More to come.