Here are my notes for today´s conference at smart City Exhibition in Bologna. As a part of the session titled Sustaining human Smart City: sharing, collaboration, community-based innovation, I was invited to prepare some introductory notes on the link of the sahring movement and cities, addressing some concepts around the idea of sharing cities and how new models of social organisation are re-shaping the way cities work and how this leads us to live in our cities in a smarter way. Besides this description of the concepts related to social innovation, I also raised some questions or challenges for the near future for this kind of innovations to reach more attention. http://www.ciudadesaescalahumana.org/2013/09/smart-city-exhibition-bologna-2013.html