Our research presents the case-study of a mobile phone based, voice-driven platform - Mobile Vaani, established with a goal to empower poor and marginalized communities to create their own local media. In this paper, we derive a comprehensive theory of change for Mobile Vaani from data gathered using the Most Significant Change technique. This paper contributes towards formulating a theory of change for technology-driven community media platforms which can be adapted to other ICTD interventions too.