Trust, authority and popularity in social information retrieval

We present a social information retrieval (SIR) model comprising the social network of actors (e.g., authors, publishers, consumers), the graph representing relations in data (e.g., publications), and the links between the social and data network that reflect activities in the network such as search, authoring, annotation, etc. Building on this hybrid network, we describe relevance in terms of the trust propagated through the network and rendered onto a given item. In particular, relevance is a function of the approval votes and the reputation of the associated sub-graph nodes. We explore a model that differentiates between approval votes from actors who are perceived authorities by the user and the approval by a wider community, representing the popular opinion.