Add to ORKGThe Semantic Web is developing slowly, but arguably surely. Two inter-related sources of delay are network effects and ontologies. The Semantic Web has come over time to rely onformal ontologies but there are many of these and they are each hard to master. The ability to link databases is compromised by the use of incompatible ontologies. But the RDF triplet format at the centre of the Semantic Web insists only on triplets of the form (object) (predicate orproperty) (subject). This paper explores the potential for a classification system that contains these three types of hierarchies (things, predicates, properties), plus a minimal set of rules on how they can be combined, to serve the needsof the Semantic Web. To this end, it surveys thero...