The sharing economy is a recent construct that brings together digital networks, platforms, resources and people in different constellations to promote resource exchange. Some of these constellations constitute markets; others thrive on and contribute to community well-being. While aspects of these arrangements are happenstance or emergent, a sequence of design decisions has led to the structuring of platforms, business models and relations in each case. These decisions were influenced by digital innovation as well as ideas about trust, sociability and the future of resource management. They respond to the global economy and also the economics of the social systems that structure resource exchange at a local level. Thus, to understand the sharing economy, we need to understand how economic systems and design decisions interact. This chapter looks at what and how people share through a study of two contrasting British sharing economy platforms to consider sustainably managing local resources in a networked age.