Mapping, GPS tracking and widely accessible mobile data have the potential to improve spatial efficiency and the way urban residents interact with public transit, transport congestion, the real estate market and monetary transactions. In Africa ICT is already enhancing urban-rural linkages, supporting the co-development of cities and their hinterlands through better market information, better access to services and easier cash transfers. The pattern of growth of African cities will no doubt be shaped by new technology. Incentives for dense and compact development fall as transport, trade and communication over longer distances become easier. But as density decreases, negative externalities (costs borne by society) increase, including congestion, pollution, segregation, infrastructure costs, loss of walkable commercial districts and the costs associated with public transit viability. Only those with cars and smart phones?