Social presence is fundamental to social constructivism and maximizing fruitful learning experiences, so distance education course designers make efforts to create technological avenues for learner creation of an online social presence. How is learner sense of social presence impacted by platform features such as course pacing, and how do on-demand versus session-based versions of the same online course differ in the degrees that learners effectively establish social presence? To probe this research question, multi-item construct scales for learner social presence, sense of community, and course satisfaction were deployed in post-course surveys for online chemistry or statistics courses in self-paced versus session-based formats. In session-based massive open online courses (MOOCs), learner sense of community was found to correlate positively with posting on the course forum, an optional aspect of the courses, and this result was statistically significant. Difficulties in providing functional pathways for learner creation of social presence and development of sense of community in self-paced, “on demand” course formats, as well as implications for future course design and research, will be discussed. These results especially impact learning of adults (age 26+) in college-level courses: because of family and work demands, adults are over-represented in part-time, evening, weekend, and online programs rather than traditional 4-year full-time programs, and their needs often drive the development of on-demand course platforms.