Regarding links: back about 12 years ago we built a software framework in the (then new) Java language named "Roku". Our ontology in Roku (Japanese for 'six') broke everything into one of six categories (Who, What, When, Where, Why and How).
C. Herzog, M. Luger, and M. Herzog. Proceedings of the ESWC'07 workshop \"Bridging the Gap between Semantic Web and Web 2.0\", Innsbruck, Austria, (June 2007)
E. Oren, J. Breslin, and S. Decker. WWW '06: Proceedings of the 15th international conference on World Wide Web, page 1071--1072. New York, NY, USA, ACM Press, (2006)