We investigated the effects of supported tagging (a prompting mechanism for students to stop and think about their writing) for team blogging on undergraduate students' reflective learning and the relationship between tagclouds and group cognition. Thirty-nine students were randomly assigned to six groups and blogged for 5 weeks. Three groups were randomly selected to receive instructor-provided keywords as supports for their tagging activity in the team blogs. Data analyses included: (1) comparing student-attached tags to the instructor-provided keywords and each participant's concept map for evidence of reflection; and (2) comparing each team's tagcloud against the team members' aggregated concept maps for the corresponding relationship between tagclouds and group cognition. Results revealed that the instructor's support in such situations might be helpful to keep students on task whereas free tagging may offer an opportunity for students' deeper processing of learning. The results also showed that tagclouds well represented students' group cognition.