Abstract
The diffusion of social networks has stimulated folksonomy-based systems (hereafter, folk-systems) to equip themselves with functionalities for the management of social relationships among users. This suggests that folk-systems and social networks have many “points of contact”. At the same time, social networks are evolving toward social internetworking systems, i.e. systems where several social networks are simultaneously considered and where users are allowed to interact with each other, even if they belong to different social networks. This trend, presumably, could extend to folk-systems. In this paper, we investigate this issue. In particular, first we introduce the concept of social inter-folksonomy based systems (hereafter, SIFS); after this, we introduce a hypergraph-based model to represent and handle a SIFS. Finally, we present an approach for the derivation of a virtual thematic folk-system from a SIFS, i.e. a fragment of SIFS centered on one or more topics which has all the properties and the functionalities of a real folk-system.