This paper conceptualizes the theoretical framework of modeling learning spaces for self-directed learning at university courses. It binds together two ideas: (a) self-directed learners' common learning spaces may be characterized as abstract niches, (b) niche characteristics are collectively determined through individually perceived affordances. The implications of these ideas on the learning design are discussed. The empirical part demonstrates the learning niche formation at the master course "Self-directed learning with social media" at two consequent years. The results of the affordance determination were used to characterize and develop the learning spaces that support self-directed learning with social media. The realization of the learning niche at two following years demonstrated that students used different social media tools for putting a similar types of affordances of the learning niche in action. This finding suggested that affordance-based niche descriptions would allow flexibility and learner-centeredness but simultaneously might enable to identify a common emergent learning space and make it reusable for modeling environments for self-directed learning courses. (Contains 1 figure and 4 tables.)