In this conference contribution we deal with the phenomenon of Massive Open Online Courses (MOOCs). Based on summary of the state of the art we discuss aspects of the learning design of MOOCs that have not been sufficiently studied. More specifically we discuss the issue of diversity and support facilities in MOOCs. We introduce the concept of learning networks and learner support services that have been developed to enable personalized learning scenarios in large-scale online environments. We report about a learning design for large-scale open online courses that has been evaluated and further developed in the last year. Last but not least we discuss future research.