In 2015, the number of global cell-phone subscriptions will surpass the number of people on the Earth--and it took a little more than 20 years for that to happen. Yet at the same time, health systems around the world are struggling to provide access to affordable healthcare for all, treat infectious disease, and train frontline health workers to provide care to vulnerable populations. TechChange's four-week online certificate TC309 course focuses on building mHealth skills that revolutionize approaches to patient care and management, point-of-care support, health education, remote monitoring, diagnostics, supply chain management & logistics and more. The notes below highlight a TC309 webinar hosted by TechChange's Kendra Keith, featuring Maeghan Orton and Dianna Kane from Medic Mobile, an organization that creates mobile and web tools that help health workers reach everyone. During the webinar, Maeghan and Dianna spoke about Medic Mobile's approach to using mobile phones for public health; they provided helpful tips, case studies from their work, and engaged in a thoughtful Q&A session with course participants.