The Urban Village:
"Human interaction networks can be inferred from billions of anonymized mobile phone records. This study, focusing on Portugal and the UK, reveals a fundamental pattern: our social connections scale with city size. People who live in a larger town make more calls and call a larger number of different people. The scaling of this relation is 'superlinear,’ meaning that on average, if the size of a town doubles, the sum of phone contacts in the city will more than double – in a mathematically predictable way."