Abstract
Services have a paramount importance for unfolding the potential of the future Internet of Things (IoT), a dense, open, cyberphysical ecosystem in which humans, conventional computing systems and daily objects straightforwardly interoperate. By summarizing our previous contributions in such novel research context, this paper promotes our vision of "Opportunistic IoT Services" and a full-fledged approach to their modeling according to their opportunistic properties. Its effectiveness and flexibility is illustrated by means of two case studies, related to the Industrial IoT and Smart City scenarios.