The document discusses the Semantic Web and linked geo data. It provides an overview of the Semantic Web initiative and its history. It also demonstrates querying linked data using SPARQL and discusses sharing data on the web by following the Linked Data principles of using URIs, HTTP URIs, publishing useful RDF information, and including links between data. The document concludes that the Semantic Web allows data to be shared and linked in a decentralized way without a single controlling ontology.