With the currently growing interest in social network services, many college courses use social network services as platforms for discussions, and a number of studies have been conducted on the use of social network analysis to measure students' participation in online discussions. This study aims to demonstrate the difference between counting posts and social network analysis of posts as a form of learners' participation in online discussions. To accomplish the goal, the study analyzed students' participation in Facebook discussions using the two methods and compared their results with those of MANOVAs. The between-group difference was significant when participation was measured by closeness centrality, but it was not significant when participation was measured by the number of posts. Although whether participation was measured by closeness centrality or by the number of posts did not make a significant difference in terms of learners' self-regulated learning level, the observed power of the closeness centrality measurement was higher than that of the number of posts measurement. These findings imply that it is important for a relational analysis to consider participation in terms of, not only the interaction between actors, but also closeness centrality, by comparing the two measurement methods.