Conceptual scheme of socioeconomic connectivity and its functions across scales of organization. At the coarsest level (top) cities and small settlements are connected via information flows that are expected, in well-developed and large urban systems, to be approximately symmetrical, as described by general statistical regularities of communication and movement (gravity laws). At the level of cities (middle) and settlements, social connectivity is expected to reflect increasing returns to population scale in social connectivity (scaling relations) and manifest itself in socioeconomic agglomeration effects, accelerating rates of economic production as well as other social and economic processes both positive and negative, see text. Finally, (bottom) the structure of connectivity is associated with transaction costs that influence social and economic organization and may facilitate informal entrepreneurship. We propose here that all these general expectations have quantitative signatures in the social networks and can be measured and evaluated using comprehensive cell-phone call records data.