SKOS (Simple Knowledge Organisation System) is 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, enabling 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). SKOS was published as a W3C Recommendation in August 2009 and is seeing growing take-up in a number of fields including (among others) cultural heritage, economics, astronomy, and local government. SKOS also looks set to play a key role in providing vocabularies for the Data Web through its use in Open Linked Data.