Discussion
OIL is much more expressive than RDFS
RDFS is powerful enough to define richer language on top of the relatively limited primitives of RDF.
There is no a universally shared KR language to support the Semantic Web.
The W3C draft, “Requirements for a Web Ontology Language”, has proposed what a web ontology language should have.
OIL is an important step towards the realization of the dream of the Semantic Web.