  Social mobilization, the ability to mobilize large numbers of people via
social networks to achieve highly distributed tasks, has received significant
attention in recent times. This growing capability, facilitated by modern
communication technology, is highly relevant to endeavors which require the
search for individuals that posses rare information or skill, such as finding
medical doctors during disasters, or searching for missing people. An open
question remains, as to whether in time-critical situations, people are able to
recruit in a targeted manner, or whether they resort to so-called blind search,
recruiting as many acquaintances as possible via broadcast communication. To
explore this question, we examine data from our recent success in the U.S.
State Department's Tag Challenge, which required locating and photographing 5
target persons in 5 different cities in the United States and Europe in less
than 12 hours, based only on a single mug-shot. We find that people are able to
consistently route information in a targeted fashion even under increasing time
pressure. We derive an analytical model for global mobilization and use it to
quantify the extent to which people were targeting others during recruitment.
Our model estimates that approximately 1 in 3 messages were of targeted fashion
during the most time-sensitive period of the challenge.This is a novel
observation at such short temporal scales, and calls for opportunities for
devising viral incentive schemes that provide distance- or time-sensitive
rewards to approach the target geography more rapidly, with applications in
multiple areas from emergency preparedness, to political mobilization.
