http://www.w3.org/2001/sw/Europe/reports/thes/1.0/guide/

SKOS-Core 1.0 is an RDF schema for representing thesauri and similar types of knowledge organisation system (KOS). SKOS-Core can be used for:

Porting existing KOS to the Semantic Web
Building simple concept schemes for the Semantic Web from scratch
SKOS stands for Simple Knowledge Organisation Systems. SKOS-Core is intended as a complement to OWL. It does provide a basic framework for building concept schemes, but it does not carry the strictly defined semantics of OWL. Thus it is ideal for representing those types of KOS, such as thesauri, that connot be mapped directly to an OWL ontology. SKOS is also easier to use, and harder to misuse than OWL, providing an ideal entry point for those wishing to use the Semantic Web for knowledge organisation.

SKOS-Core also provides a framework for linking concepts to the words and phrases that are normally used by people to refer to them. This valuable information, once captured, can be used to support a number of tasks, such as automated classification of web documents, and automated multilingual translation of glossaries.

This guide first describes the SKOS meta-model, and introduces the terminology that will be used throughout. There follows a description of the features of the SKOS-Core 1.0 schema, with examples of how to use them. Finally there are guidelines for using SKOS concept schemes for subject-based indexing of web resources.