One oft-heard criticism about MOOCs is the fact that few learners complete the course and finally obtain a certificate. This article addresses this issue on the basis of the analysis of the MOOC “Decouvrir la science politique” (whose acronym is Louv3x and is available on the edX platform). With a retention rate of 18%, this MOOC scores above the average. In order to refine empirically the question, and building on existing literature, the authors draw a distinction between levels of active retention and passive retention. In this perspective, the paper digs into data – both quantitative and qualitative – collected throughout the MOOC and explores several explanatory factors of retention and motivation for the learners and the teaching team