Structuring folksonomies with implicit tag relations

Tagging systems allow users to assign arbitrary text labels (i.e., tags) to various types of resources, such as photos or web pages, to facilitate future retrieval and selective sharing of contents. The resulting system of classification is referred to as a folksonomy. The uncontrolled nature of tags leads to inconsistencies in the usage of terms which impairs the utility of the system. Approaches to this problem that map tags to concepts of external knowledge representations, such as ontologies, are often inapplicable since they require that corresponding concepts exist and that they reflect the meaning of tags as intended by the users. In this paper, we present the notion of implicit tag relations. Our aim is to improve the accessibility of contents in tagging systems without significantly reducing the flexibility and universal applicability of tags. Instead of explicitly relating tags to each other, we propose to give users the ability to retroactively alter folksonomies by changing the tags of many resources with a single operation. This way, the usage of tags can be harmonized and it can be controlled how they are used in combination. We highlight the benefits of our approach compared to explicit tag relations and discuss important implications as well as its limitations.