The paper introduces a virtual collaborative learning setting called "Net Economy," which we established as part of an international learning network of currently seven universities. Using the Community of Inquiry framework as guidance and Canonical Action Research (CAR) as the chosen research design, the discussion forum of the online course is assessed regarding its critical thinking value. We thereby measure critical thinking with the help of the according model provided by Newman et al. (1995), which differentiates 40 indicators of critical thinking from ten different categories. The calculated critical thinking ratios for the analyzed two discussion threads indicate a strong use of outside knowledge, intensive justification as well as critical assessment of posts by the students. But at the same time there are also weak spots, like manifold repetitions. Based on these results we derive changes for the next course cycle in order to improve the critical thinking of the students. [For the full proceedings, see ED562095.]