Online education based on small self-managing groups, with slight supervision by a professional tutor, is a strategically interesting methodology for lifelong learning. This solution may combine aspects of cost-effectiveness (reducing tutors' work) with the demands for active and engaging learning methods based on the exchange and sharing of experiences. In such a context, how can information on collaborative attitudes and behaviour be gathered? A typical tool for online learning activities is the threaded web forum. This study proposes a methodology for assessing effective collaborative interactions within the add-on module, Forum Plus, for the Moodle learning management system (LMS). The methodology here presented is able to supply an early overview of the level of effectiveness of the collaborative group and therefore it may provide a useful instrument to guide further qualitative observations conducted directly in the web forum.