Dublin Core Metadata Initiative provides a set of metadata for describing numerical and physical resources, esp. for bibliographic purposes. Widespread properties in the Web of Data include:
- dcterms:creator to specify the maker of a resource,
- dcterms:date to specify a date related to the resource, or
- dcterms:description to add a description of a resource, or
- dcterms:subject to specify the topic of a resource.
Friend-of-a-Friend project (FOAF) proposes a widespread vocabulary for the description of persons, their social links and relations to other objects. Several social networks are using FOAF vocabulary to expose their data:
FOAF data establishes a distributed social network.
Semantically-Interlinked Online Communities (SIOC) is another very important vocabulary to describe social networks. SIOC exporters exist for Wordpress, Drupal or vBulletin. Prominent properties in the SIOC vocabulary are, as e.g., :
- sioc:hasCreator describes the creator of an object
- sioc:content text-only representation of content (as e.g. a blog post)
- sioc:topic indicating the topic of a resource.
Simple Knowledge Organisation System (SKOS) is used to describe concept hierarchies such as taxonomies, folksonomies, or thesauri. SKOS provides properties to represent subsumption hierarchies:
- skos:narrower describes a more specific concept,
- skos:broader describes a more general concept.
SKOS vocabulary is a powerful tool to describe domain ontologies, where the rdfs:subClassOf would be insufficient or not suited to describe a hierarchical relationship. Just take into account the following example:
|Albert Dubois-Pillet: The Banks on the Marne at Dawn (c. 1888)|
A pointilistic painting, which is also an impressionistic painting.
But not all pointilistic paintings are also impressionistic paintings.
Thus, Pointilistic Painters in general are not a valid subclass of Impressionistic Painters, simply because there are some pointilistic painters that are not counted as impressionistic painters, but started a new art style like Henri-Edmond Cross, who developed from Pointilism to Neo-Impressionism and went on to Fauvism. Nevertheless, the concept 'Impressionistic Painters' is a more general concept than the concept 'Pointilistic Painters', because Pointilism branched from the Impressionistic movement.
Thus we might say:
- ex:ImpressionisticPainters skos:narrower ex:PointilisticPainters .
ex:PointilisticPainters skos:broader ex:ImpressionisticPainters .