Abstract:This document defines the Simple Knowledge Organization System (SKOS), a common data model for sharing and linking knowledge organization systems via the Web. Many knowledge organization systems, such as thesauri, taxonomies, classification schemes and subject heading systems, share a similar structure, and are used in similar applications. SKOS captures much of this similarity and makes it explicit, to enable data and technology sharing across diverse applications. The SKOS data model provides a standard, low-cost migration path for porting existing knowledge organization systems to the Semantic Web. SKOS also provides a light weight, intuitive language for developing and sharing new knowledge organization systems. It may be used on its own, or in combination with formal knowledge representation languages such as the Web Ontology language (OWL). This document is the normative specification of the Simple Knowledge Organization System. It is intended for readers who are involved in the design and implementation of information systems, and who already have a good understanding of Semantic Web technology, especially RDF and OWL.

excerpt from Introduction: The Simple Knowledge Organization System is a data sharing standard, bridging several different fields of knowledge, technology and practice. In the library and information sciences, a long and distinguished heritage is devoted to developing tools for organizing large collections of objects such as books or museum artifacts. These tools are known generally as “knowledge organization systems” (KOS) or sometimes “controlled structured vocabularies”. Several similar yet distinct traditions have emerged over time, each supported by a community of practice and set of agreed standards. Different families of knowledge organization systems, including “thesauri”, “classification schemes”, “subject heading systems”, and “taxonomies” are widely recognized and applied in both modern and traditional information systems. In practice it can be hard to draw an absolute distinction between “thesauri” and “classification schemes” or “taxonomies”, although some properties can be used to broadly characterize these different families (see e.g. BS8723 Structured Vocabularies for Information Retrieval Part 3: Vocabularies Other Than Thesauri, British Standards Institution (BSI), 2005). The important point for SKOS is that, in addition to their unique features, each of these families shares much in common, and can often be used in similar ways. However, there is currently no widely deployed standard for representing these knowledge organization systems as data and exchanging them between computer systems.

Abstract: The Simple Knowledge Organization System (SKOS) is an RDF vocabulary for representing semi-formal knowledge organization systems (KOS), such as thesauri, taxonomies, classification schemes and subject heading lists. Because SKOS is based on the Resource Description Framework (RDF) these representations are machine-readable and can be exchanged between software applications and published on the World Wide Web. SKOS has been designed to provide a low-cost migration path for porting existing organization systems to the Semantic Web. SKOS also provides a lightweight, intuitive conceptual modeling language for developing and sharing new knowledge organization systems (KOSs). It can be used on its own, or in combination with more formal languages like the Web Ontology Language (OWL). SKOS can also be seen as a bridging technology, providing the missing link between the rigorous logical formalism of ontology languages such as OWL and the chaotic, informal and weakly-structured world of Web-based collaboration tools, as exemplified by social tagging applications. The aim of SKOS is not to replace original conceptual vocabularies in their initial context of use, but to allow them to be ported to a shared space, based on a simplified model, enabling wider re-use and better interoperability.

Triplify is a small plugin for database-driven web applications which exposes data from Web applications as RDF, Linked Data and/or JSON;