Tagging Ontology – Towards a Common Ontology for Folksonomies

Collaborative tagging represents the process by which many users describe resources (e.g. web pages or photos) with free-form keywords (tags). The combination of all users tags for a certain resource reflects the common understanding of that resource from the users’ point of view, which is called “folksonomy”. Today there are many systems making use of folksonomies, most notably del.icio.us and flickr. These systems (also referred to as “social software”) allow the users to publish their taggings for the benefit of the community, mostly via RSS feeds. The problem is, that there is no common agreement about the semantics of a tagging, and thus every system uses a different representation, hindering interoperability between systems and the automated processing by software agents. In this paper we use Semantic Web technologies to develop an ontology for folksonomies, making interoperability and automated processing feasible. In order to validate our ontology we extract sample tagging data from del.icio.us and feed it into our ontology. Finally, we run some SPARQL queries against this data to prove that the folksonomic information can easily be accessed within our ontology.