This paper deals with how to calculate semantic similarity between user profiles. They want to find for example similar users, which share common interests.
F. Abel, N. Henze, E. Herder, and D. Krause. User Modeling, Adaptation, and Personalization, 18th International Conference, UMAP 2010, Big Island, HI, USA, June 20-24, 2010. Proceedings, volume 6075 of Lecture Notes in Computer Science, page 16-27. Springer, (2010)