This paper outlines the opportunities and challenges which have guided UN Global Pulse since its inception in 2009. The paper builds on some of the most recent findings in the field of data science, and findings from our own collaborative research projects. It does not aim to cover the entire spectrum of challenges nor to offer definitive answers to those it addresses but to serve as a reference for further reflection and discussion. The rest of the document is organised as follows: Section one lays out the vision that underpins Big Data for Development; Section two discusses the main challenges it raises; Section three discusses its application. The concluding section examines options and priorities for the future.