There has been much effort on studying how social media sites, such as
Twitter, help propagate information in different situations, including
spreading alerts and SOS messages in an emergency. However, existing work has
not addressed how to actively identify and engage the right strangers at the
right time on social media to help effectively propagate intended information
within a desired time frame. To address this problem, we have developed two
models: (i) a feature-based model that leverages peoples' exhibited social
behavior, including the content of their tweets and social interactions, to
characterize their willingness and readiness to propagate information on
Twitter via the act of retweeting; and (ii) a wait-time model based on a user's
previous retweeting wait times to predict her next retweeting time when asked.
Based on these two models, we build a recommender system that predicts the
likelihood of a stranger to retweet information when asked, within a specific
time window, and recommends the top-N qualified strangers to engage with. Our
experiments, including live studies in the real world, demonstrate the
effectiveness of our work
