The emergence of Massive Open Online Courses (MOOCs) is focusing all its attention on open education. There is growing interest in creating MOOCs, which can be done by transferring OCW courses to MOOC format. However, a series of doubts arise regarding the pros and cons implied in this transformation. In this paper we discuss the conclusions derived from our experience at Universidad Carlos III de Madrid with a widely disseminated OCW course that was satisfactorily converted into a MOOC. This experience has allowed us to compare two different models of open education initially based on the same content. We also analyze the difficulties incurred in the transformation process and present strategies to successfully carry out this change.