This white paper explores the many facets of OpenStreetMap (OSM) in development and its "sustainability." It examines the definition of sustainability in ICT for Development (ICT4D) and four dimensions of "sustained benefit" which can help us to understand factors that will influence longer term success of work involving OSM in development. The paper outlines challenges for seven different actors which typically work with OSM in developing economies. It deals with challenges that tend to arise for these actors in achieving sustainability in the four dimensions. It then suggests a way forward for funders, practitioners, and others to move toward greater benefits for all given the constraints of OSM globally, the ethical considerations of digital open mapping, and the challenges of open source and open data projects generally as technology matures.