What is Ontology? See the brief discussion here.

One of the main projects of ContentMold is to combine ontologies of knowledge artifacts (books, articles, etc) with ontologies of the domains they involve. This structure would allow precise navigation within and across texts, facilitating the creation of personalized curricula.

It's a real big rabbit-hole, and I haven't made much progress so far. We'll see. The main project I imagine to incubate this Semantic Web infrastructure is MoldAbout.