Despite the growth of MOOCs, Lifelong learners confront many difficulties related to the attendance of courses on MOOCS. Lifelong learners are often very different in terms of background, ability, experience, and prior knowledge but they are required to follow the same content. This explains the low average completion rate for MOOCs. The research presented in this paper aims to define the functional and technical architecture to personalize content in Massive Open Online Courses in a Lifelong Learning perspective. The term content refers to videos, tutorials, documents, exercises, and quizzes in MOOCs. This work is dedicated to teachers, MOOCs designers, MOOCs providers, pedagogical engineers, and researchers in e-Learning and learning analytics. This work takes place within the context of a European project called MOOCTAB (Massive Online Open Course Tablet).