Ontology engineering processes in truly distributed settings like the Semantic Web or global Peer-to-Peer systems may not be adequately supported by conventional, centralized ontology engineering methodologies. In this chapter, we present our work towards the DILIGENT methodology, which is intended to support
engineer and evolve
ontologies. We show partial results on how the DILIGENT process model has been applied in two case studies, in particular (1) in a computer science department where we investigated a fine-grained methodological approach for argumentation, and (2) in a virtual organizational setting in the tourism domain with the support of a Peer-to-Peer system.