Comments on informal meaning of the RDFS vocabulary

The RDF Schema document provides intended meanings for some of the RDFS
vocabulary that is not supported by the RDF Semantics.  Vocabulary that
fits into this category includes rdfs:label and rdfs:comment.  The
distinction between these meanings and the meanings supported by the RDF
semantics, such as for rdfs:subClassOf, needs to be stated much more
clearly.  

This is particularly important because of the notion of social meaning in
RDF.  Without a clear distinction, the reader can be left with the
impression that there is no difference between social meaning and model
theory meaning.