SIOC/TagCloudOntology

<tc:TagCloud>
  <rdf:Bag rdf:about="http://example.com/tag" />
    <rdf:li rdf:resource="http://example.com/tag/galway" />
    <rdf:li>
      <tc:Tag rdf:about="http://example.com/tag/ireland">
        <rdfs:label>Ireland</rdfs:label>
        <tc:frequency>6</tc:frequency>
        <tc:used_by rdf:resource="..." />
OR      <foaf:Maker rdf:resource="..." />
        <tc:used_when>...</tc:used_when>
OR      <dc:date>...</dc:date>
        <tc:coocurring_tag rdf:resource="http://example.com/tag/galway" />
OR      <tc:occurs_with rdf:resource="http://example.com/tag/galway" />
        <rdfs:seeAlso rdf:resource="..." />
OR      <tc:used_where rdf:resource="http://example.com/photo/cloud/galway_bay.jpg" />
    </rdf:li>
  </rdf:Bag>
</tc:TagCloud>