“Ontologies are enabling technology for the Semantic Web. They are a means for people to state what they mean by the terms used in data that they might generate, share, or consume. Folksonomies are an emergent phenomenon of the Social Web. They arise from data about how people associate terms with content that they generate, share, or consume. Recently the two ideas have been put into opposition, as if they were right and left poles of a political spectrum. This is a false dichotomy; they are more like apples and oranges. In fact, as the Semantic Web matures and the Social Web grows, there is increasing value in applying Semantic Web technologies to the data of the Social Web. This article is an attempt to clarify the distinct roles for ontologies and folksonomies, and previews some new work that applies the two ideas together – an ontology of folksonomy.” (Tom Gruber)