The internet of things (IoT) is a technology that has the capacity to transfigure the way that we live, in sectors ranging from transport to health, from entertainment to our communications with government. This incredible opportunity also presents a number of major challenges. The growth of the number of devices and the pace of that development pose challenges to our security and freedoms as we struggle to develop the policies, standards and governance that shape this development without hindering innovation. This article talks about the development of IoT, its different definitions, and some of its key application areas. Security and privacy reflections and challenges are discussed in general and in the context of these applications.