This paper presents findings from the pattern of participation and discourse analysis of the online interaction among in-service teachers in the teacher training institute in Singapore. It was found that the teachers formed a knowledge-building community and jointly discussed issues related to integrating information technology into the classroom. There was evidence that teachers formed a socially cohesive community and their participations were active. However it was found that in-depth and sustainable online interaction were lacking. The authors suggest searching for ways to promote deep and sustainable online interaction, especially in terms of getting participants to detect the gap in ideas and challenging assumptions. (Contains 3 figures and 6 tables.)