While there have been many studies on instructional and on-task side of computer supported collaborative learning (CSCL), social and non-task side of the CSCL has received less attention. This paper observes and studies the pattern of non-task social messaging over a period of time in online Seminar rooms -designed for learning activities- as well as Coffee shops- designed for informal conversations. The objective is to firstly uncover the pattern of social interactions in the online collaborative learning environment and, secondly to understand how the level of social interactions changes over time and what factors facilitate and lead such changes. Transcript Analysis Tool (TAT) has been used to code discussions of three online classes during a 10-week postgraduate summer course in an Australian university. Findings have indicated existence of a substantial amount of non-task interactions among students. Furthermore, the results have shown a larger amount of non-task interactions occurred at the beginning and end of the semester as well as during some special occasions. Students' willingness to share personal and work-related experiences with other classmates is amongst top factors leading such trend in social interactions in the environment.