The widespread diffusion of social media in the schools is boosted from the recent technological innovations and gains its theoretical foundation from pedagogical theories inspired to social constructivism, on the basis of which learning activities supported by social media enrich students' learning processes, improving their subject-related and transversal competencies. Indeed, the auto-directive nature of social media stimulates students to immerse themselves into active learning processes, formal and informal, within and outside the classroom. In this work a reflection on the role played by social media at school is developed, in terms of innovation of educational processes, of improvement of teacher professionalism, of the adoption of learning strategies more in line with students' needs. This reflection is supported by a discussion on the outcomes of a survey lead with a sample of teachers and students from thirty schools who experimented, along a whole scholastic year, interdisciplinary and project-based activities based on the use of social media.