Social bookmarking and tagging systems currently do not provide a uniform way to share and reuse tag data amongst users or communities. Although most popular Web 2.0 sites such as del.icio.us, Flickr or YouTube provide XML or JSON-based data using open APIs, there is no uniform structure or semantics to represent tag data.
We present a semantic model (called SCOT) which can be used to represent the structure of and relations between the tag data created in social tagging spaces. The SCOT model can provide a comprehensive set of information related to the process of social tagging. An associated website called int.ere.st helps users to enhance the sharing and exchange of tag data among people or between various online communities. int.ere.st provides interlinked semantic data using SCOT and the popular Semantic Web vocabularies FOAF, SIOC and SKOS. Also, the results of user contributions in the site provide a means to build social networks based on social tag data and their associated semantic relations.