The purpose of this study is to examine the impacts of transactive memory system (TMS) and interaction platforms in computer-supported collaborative learning (CSCL) on social presence perceptions and self-regulation skills of learners. Within the scope of the study, social presence perceptions and self-regulation skills of students in collaborative groups constructing knowledge in wiki, blog, podcast and Facebook platforms in CSCL processes were compared. The study is designed as a pretest and post-test control group study and was carried out with 97 university students. Social presence and self-regulation scales were administered as pretest in the study. At the end of process, social presence, self-regulation, transactive memory scales and semi-structured student opinion forms were administered as post-test. When the findings were examined, it was seen that interaction platforms and the TMS level of the group did not have a significant impact on social presence perception individually; yet common impact of these two variables was significant. When the impact of interaction platforms and the TMS on self-regulation skills was examined, it was found that whilst interaction platforms had a significant impact, the TMS alone and interaction platforms--TMS common impact were not significant.