  Social influence has been shown to create significant unpredictability in
cultural markets, providing one potential explanation why experts routinely
fail at predicting commercial success of cultural products. To counteract the
difficulty of making accurate predictions, "measure and react" strategies have
been advocated but finding a concrete strategy that scales for very large
markets has remained elusive so far. Here we propose a "measure and optimize"
strategy based on an optimization policy that uses product quality, appeal, and
social influence to maximize expected profits in the market at each decision
point. Our computational experiments show that our policy leverages social
influence to produce significant performance benefits for the market, while our
theoretical analysis proves that our policy outperforms in expectation any
policy not displaying social information. Our results contrast with earlier
work which focused on showing the unpredictability and inequalities created by
social influence. Not only do we show for the first time that dynamically
showing consumers positive social information under our policy increases the
expected performance of the seller in cultural markets. We also show that, in
reasonable settings, our policy does not introduce significant unpredictability
and identifies "blockbusters". Overall, these results shed new light on the
nature of social influence and how it can be leveraged for the benefits of the
market.
