About the Authors

Francesco Calabrese

fcalabre@ie.ibm.com

Affiliations IBM Research, Dublin, Ireland, Senseable City Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America

Zbigniew Smoreda

Affiliation Sociology and Economics of Networks and Services Department, Orange Labs, Issy-les-Moulineaux, France

Vincent D. Blondel

Affiliations LIDS, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America, Department of Mathematical Engineering, Université Catholique de Louvain, Louvain-la-Neuve, Belgium

Carlo Ratti

Affiliation Senseable City Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America

Competing Interests

Francesco Calabrese is employed by IBM Research. Zbigniew Smoreda is employed by Orange Labs. These affiliations do not alter the authors' adherence to all PLoS ONE policies on the sharing of data and materials.

Author Contributions

Conceived and designed the experiments: FC ZS VB CR. Performed the experiments: FC. Analyzed the data: FC ZS VB. Contributed reagents/materials/analysis tools: FC. Wrote the paper: FC ZS VB CR.