Service-Oriented Computing (SOC) builds upon the intuitive notion of service already known and used in our society for a long time. SOC-related approaches are based on computer-executable functional units that often represent automation of services that exist at the social level, i.e., services at the level of human or organizational interactions. With the increasing adoption of SOC, more complex scenarios mixing computational and social services are emerging, raising the need to better understand the relationship between social and computational services and to specify and model them accordingly. In this paper we present our ontology-based approach to dynamic service provisioning. Our approach aims at improving the current state of the art by allowing an explicit distinction between social and computation services and dynamic service provisioning support for these two types of services. We illustrate the applicability of our approach with a use case scenario in the health care domain.