PropertyValue
http://www.w3.org/1999/02/22-rdf-syntax-ns#type
http://www.w3.org/ns/prov#value
  • For sexually explicit content, our filter mainly relies on algorithms that look at many factors, including keywords, links, and images. [support.google.com...] If, as you say, the images themselves are not sexually explicit take a look at the captions, surrounding text, backlinks (anchor text, surrounding copy, site niche, etc.), and hotlinking sites.
http://www.w3.org/ns/prov#wasQuotedFrom
  • webmasterworld.com