After the work of Nicola Guarino, formal ontology is available today as a powerful conceptual tool for information systems modelling. In particular, for shared conceptual models, the ontological characterization of predicative symbols may help clarifying their intended semantics. Yet, about twenty five years after Guarino's seminal paper, the penetration of formal ontological tools in modelling languages, as well as the spread of highly formalized conceptual models in business information systems, is still relatively low. This paper aims at elaborating some hypotheses about this fact. Concrete conditions for stipulating semantic agreements, depending on socio-technical architectures, are compared with assumptions of descriptive metaphysics as implemented in today's ontology engineering. As an outcome of this analysis, a clearer separation between linguistic concepts produced in human semiotic processes and metaphysic postulates emerges as a key move for overcoming difficulties and open the way to further developments.