Abstract
This chapter discusses user profiles as an important component of online social networks (OSN). A special category of OSN includes professional social networks, where so called professional profiles are significant.
They enable to connect not only people, but also projects to people, courses to students, etc. A powerful tool for representing profiles is ontologies, particularly various classification hierarchies.
A contribution of this approach is a matching framework able to consider profiles, whose some features are described by concepts from classification hierarchies. Moreover, users can assign weights to these concepts and influence an associated similarity measure.
We discuss the notions of similarity and compatibility of such profiles and show some new possibilities how to tackle the matching problem.