Mining data produced by students involved in communication through forum-like tools can help revealing aspects of their communication. In this paper we propose an approach to the construction of models to highlight structural properties of learning groups based on a relational perspective (analysis of chains of references) and the use of Social Network Analysis techniques. These models can be useful both for the tutor and the participants. We begin by introducing the overall approach, then we describe how the models are constructed and finally we present preliminary results from the integration of these ideas in a forum-type tool. (http://portal.acm.org/citation.cfm?id=1149293.1149360)