Product Lifecycle Management (PLM) aims at an integrated management of all product-related information and processes through the entire lifecycle. Within an extended enterprise, systems interact in order to share data and information throughout a product lifecycle. Beyond this computing point of view, individuals may be spread throughout the world and that is the reason why the same information on the same product shared through the same PLM system within the same extended enterprise may lead to different interpretations. Individual cognition, knowledge and particularly tacit knowledge have to be considered during the design of such computing systems. The aim of this work is to outline a semantic interoperability between a collaborative platform and a PLM system. Such interoperability allows individuals to construct a shared understanding, supporting tacit knowledge sharing, i.e. knowledge that cannot be made explicit. Our approach leads then to focus on the impact of individual cognition on PLM systems.