The SCOT(Social Semantic Cloud Of Tags) ontology is to semantically represent the structure and semantics of a collection of tags and to represent social networks among users based on the tags.
A. Plangprasopchok, K. Lerman, and L. Getoor. Proceedings of the 16th ACM SIGKDD International Conference on Knowledge Discovery and Data Mining, page 949--958. New York, NY, USA, ACM, (2010)
H. Kim, S. Scerri, J. Breslin, S. Decker, and H. Kim. DCMI '08: Proceedings of the 2008 International Conference on Dublin Core and Metadata Applications, page 128--137. Dublin Core Metadata Initiative, (2008)
T. Rattenbury, N. Good, and M. Naaman. SIGIR '07: Proceedings of the 30th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, page 103--110. New York, NY, USA, ACM Press, (2007)
C. Cattuto, D. Benz, A. Hotho, and G. Stumme. Proceedings of the 3rd Workshop on Ontology Learning and Population (OLP3), page 39--43. Patras, Greece, (July 2008)
P. Mika. Proceedings of the 4th International Semantic Web Conference, volume 3729 of Lecture Notes in Computer Science, page 522-536. Springer, (2005)