There have been attempts: FOAF: https://en.wikipedia.org/wiki/FOAF_(ontology) XF...

		groby_b on Oct 6, 2016 \| parent \| context \| favorite \| on: Are closed social networks inevitable? (2010) There have been attempts: FOAF: https://en.wikipedia.org/wiki/FOAF_(ontology) XFN: https://en.wikipedia.org/wiki/XHTML_Friends_Network There's probably more. There's always more standards :)

So many to choose from!