  The dynamics of technological, economic and social phenomena is controlled by
how humans organize their daily tasks in response to both endogenous and
exogenous stimulations. Queueing theory is believed to provide a generic answer
to account for the often observed power-law distributions of waiting times
before a task is fulfilled. However, the general validity of the power law and
the nature of other regimes remain unsettled. Using anonymized data collected
by Google at the World Wide Web level, we identify the existence of several
additional regimes characterizing the time required for a population of
Internet users to execute a given task after receiving a message. Depending on
the under- or over-utilization of time by the population of users and the
strength of their response to perturbations, the pure power law is found to be
coextensive with an exponential regime (tasks are performed without too much
delay) and with a crossover to an asymptotic plateau (some tasks are never
performed). The characterization of the availability and efficiency of humans
on their actions revealed by our study have important consequences to
understand human decision-making, optimal designs of policies such as for
Internet security, with spillovers to collective behaviors, crowds dynamics,
and social epidemics.
