Social media are becoming an increasingly relevant channel for user involvement. However, their uptake in Living Labs environments, as a means to engage users in innovation processes, is still limited. The aim of this paper is to explore challenges and opportunities related to the usage of social media for user involvement in co-creative processes, The findings presented emerge both from the available literature and case studies, and emphasise four different dimensions influencing user engagement: content, community, platform and innovation process. Based on these dimensions, the authors propose a basic framework, intended as the point of departure for taking the next step toward the construction and verification of theoretical constructs that can help inform and guide future innovation projects.