Both Information and Communication Technologies (ICT) and the communication tools, synchronous and non-synchronous, that ICT offer are being used with more and more frequency in the university of Lleida (UdL). The aim is to guarantee a good virtual communication in the learning processes. In the present research 8 virtual forums done in the Sakai virtual campus in UdL have been analysed. These 8 virtual forums have been realized in 4 different subjects. It has been decided to analyse 2 forums of each subject, one done at the beginning of the course and the other at the end. The aim has been to compare and observe if the experience has any kind of influence in the improvement of the interaction and in the message’s quality. Furthermore many factors which can have an influence in the communication and interaction among students have been also observed. The methodology used is both quantitative and qualitative. To examine the features of networked interaction graphs has been used. In the qualitative analysis, contents of the computer messages were categorized by Gunawardena’s classification (1997). The results of the study revealed that opinion messages of sharing information and comparison are the most used. Students have also built messages with examples and clarifying concepts. However, messages of negotiation, disagreement, synthesis and conclusion are hardly used. It was found that it is very important the presence of the mediator’s role, because if this figure is not in the forum, not only did the interaction decrease notably, but also contents of messages are more superficial.