This article analyses the challenges teachers face when entering a digital and open online environment in higher education. Massive open online courses (MOOCs) have become a popular phenomenon, making online learning more visible in the educational agenda; therefore, it is appropriate to analyse their expansion and diversification to help inform the next generation of courses. In this article, MOOCs are contextualised in a historical and wider approach to online education, building upon lessons learned from open and distance education, and exploring the introduction of technologies in providing higher education to massive populations over the past 45 years. In particular, the research study presented in this article used the "open scholarship" approach to analyse many of the changes that can occur in teaching when an open context applies, as in the case of MOOCs. Taking into account that a collaborative online learning experience is influenced by the simultaneous presence and overlap of cognitive, social and teaching elements, the study also used the "community of inquiry" model as a theoretical framework. In the study, 24 teachers (from the Universidad Nacional de Educación a Distancia [UNED] in Madrid, Spain) were surveyed about their experiences of MOOCs in terms of their current tasks, and the main changes they have observed compared to teaching in a more traditional electronic learning (e-learning) environment (at both graduate and postgraduate levels). These changes in roles, as well as teachers' views about the impact of "massiveness" and "openness" on their understanding and teaching practice, are presented and analysed. Finally, the article also discusses how the evolution towards adapted learning, collaborative learning and assessment supported by technical tools, for example, was already in progress at UNED before MOOCs were initiated.