Providing tools for dialogue exchange does not ensure that students will respond to team mate postings or that online groups will grow in cohesiveness. Students decide whether or not to reply, and it is increasingly important to understand how students make these decisions due to the increase in distance education, millenials, and asynchronous teamwork in the workplace. This exploratory qualitative study was based on an interpretivist philosophy to understand how students reply to discussion postings. Students from two Master's-level research classes were asked why they chose to respond to certain discussion postings and why they chose not to reply to certain postings. The reasons why students responded to postings were clustered into four themes: group process criteria, leadership criteria, social criteria, and judgment criteria. The reasons why students did not respond fell into the criteria of applicability, judgment, leadership, and social criteria. Implications for e-learning instructors and practitioners are discussed in terms of promoting social presence and facilitating collaborative group work. (Contains 1 table.)