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GoodRelations is a lightweight ontology for annotating offerings on the Web. It is to our knowledge the first non-toy vocabulary for describing the types of goods and terms and conditions of items and services offered on the Web. The GoodRelations ontology complements products and services ontologies, like eClassOWL, by providing the vocabulary for expressing things like

that a particular Web site describes an offer to sell cellphones of a certain make and model at a certain price,

that a pianohouse offers maintenance for pianos that weigh less than 150 kg,

or that a car rental company leases out cars of a certain make and model from a particular set of branches across the country.