Flickr has announced a new addition to the API — Machine Tags:
# Wait, aren’t machine tags just RDF?
No, machine tags are not RDF; they could play RDF on television, though.
See also :
# Huh, what is RDF ?
RDF Describes Flickr. That’s really all you need to know about RDF.
Of course it’s not quite there, using fixed namespace prefixes instead of URIs, but it’s close enough.
Now, where’s that list of canonical namespace prefixes?