Business models on the basis of digital content require sophisticated descriptions of that content, as well as service-oriented carrier architectures that allow to negotiate and enforce contract and license schemes in heterogeneous digital application environments. We describe Knowledge Content Objects (KCO), that provide expressive semantic descriptions of digital content, based on an ontology of Information Objects, built under the DOLCE, DnS and Plan Ontologies (DDPO). In particular, we discuss how this structure supports business requirements within the context of paid content. Interactions between agents are embedded into digital infrastructures that are implemented on an advanced knowledge content carrier architecture (KCCA) that communicates via a dedicated protocol (KCTP). We show how this architecture allows to integrate existing digital repositories so that the content can be made available to a semantically rich digital environment.