The site presents a hierarchical organization for Wikipedia articles with respect to their semantic similarity and provides search and navigation facilities over the hierarchy. The hierarchy is constructed as a recursive division of the English Wikipedia graph into dense subgraphs (graph communities) and can be considered as an extension to the Wikipedia category structure. Unlike Wikipedia categories that are primarily authored by humans, the community hierarchy is fully automatic, purely link-based and reflects the global link structure of Wikipedia.
S. Javanmardi, D. McDonald, and C. Lopes. Proceedings of the 7th International Symposium on Wikis and Open Collaboration, page 82--90. New York, NY, USA, ACM, (2011)