Research in the field of computer supported collaborative learning stresses the need to foster the collaborative process in view of attaining optimal cognitive involvement of all participants, a higher level of metacognitive regulation and an increased level of affective involvement. The present study involved 80 third-year university students, enrolled in the educational sciences, in a quasi-experimental study to research the impact of a scripting approach to support their collaborative work in asynchronous online discussion groups. Students in the experimental condition were required to label all their contributions to the discussions using Bloom's taxonomy. The results point at a significant differential impact of this scripting approach: a higher level of cognitive processing was attained and students in the experimental condition mirrored a higher degree of metacognitive regulation in relation to planning, achieving clarity and monitoring. Lastly, the students in the experimental condition were more affectively involved. Given the two-week duration of the study, it is remarkable that the positive impact of the scripting approach was attained after this relatively short period of time. (Contains 2 tables.)