  Novel aspects of human dynamics and social interactions are investigated by
means of mobile phone data. Using extensive phone records resolved in both time
and space, we study the mean collective behavior at large scales and focus on
the occurrence of anomalous events. We discuss how these spatiotemporal
anomalies can be described using standard percolation theory tools. We also
investigate patterns of calling activity at the individual level and show that
the interevent time of consecutive calls is heavy-tailed. This finding, which
has implications for dynamics of spreading phenomena in social networks, agrees
with results previously reported on other human activities.
