Structure and diffusion in a mobile communication network

Large electronic databases such as anonymous phone logs of an operator can provide records of human communication patterns and make it possible to explore the structure of the social network, it forms. Here we study the communication patterns of millions of mobile phone users, allowing us to get insight to both the local and global structure of a society-wide communication network. We observe a coupling between interaction strengths and the local structure of the network, and find that social networks are robust to the removal of the strong ties, but fall apart following a phase transition if the weak ties are removed. We show that this coupling slows down the diffusion of information due to it being trapped in communities. We also find that for information diffusion, both weak and strong ties are ineffective.