With the rise of massive open online courses (MOOCs), the facilitation of interpersonal interactions at scale has been widely contested, especially when learner interactions are limited to forum activity. This study examined whether interpersonal interactions in platform-based MOOC forums allowed for the development of social presence – a perceived sense of somebody being present and “real” in an online course. Learner perceptions of social presence were collected from three online courses via the Community of Inquiry questionnaire. The differences in perceptions were statistically compared between learners with various levels of engagement. The results reveal significant differences in perception of social presence depending on an individual’s level of forum activity. Individuals with sustained forum contributions developed strongest social presence perceptions. The level of social presence differed in courses of varying size and duration. Specifically, MOOCs with higher participation rates in social interactions, and shorter course duration, were associated with lower familiarity with another person.