The study describes the factors that render possible and restrain students' learning when they try to develop new knowledge through collaboration in a net-based learning environment. The pedagogical platform takes as its starting point a framework of socio-cultural theories of learning and is based on dialogues and collaborative situations in small groups. Results of the study have been extracted using statistical analysis of students' understanding of the concepts of knowledge and learning as well as self-confidence. To ascertain whether or not students' learning has benefited from the net-based dialogues, background factors such as gender, socio- economic background, and ethnicity have been accounted for in the overall analysis. Results show that there are relatively big differences between the students' approach to knowledge and learning and that this appears to influence their behaviour during the course. The analysis shows that only some students develop a good ability for using dialogues as an important learning resource, while others do not choose to utilise this opportunity. Furthermore, results show that students' descriptions of themselves are clearly related to their course activity and to their examination results. A surprising discovery is that students with a non-academic background seem to utilise this opportunity for collaboration to a much greater extent that others, and also achieve better examination results.