A scheme that publishes aggregate information about sensitive data must resolve the trade-off between utility to information consumers and privacy of the database participants. Differential privacy [5] is a well-established definition of privacy—this is a universal guarantee against all attackers, whatever their side-information or intent. In this paper, we present a universal treatment of utility based on the standard minimax rule from decision theory [13] (in contrast to the utility model in [8], which is Bayesian). In our model, information consumers are minimax (riskaverse) agents, each possessing some side-information about the query, and each endowed with a loss-function which models their tolerance to inaccuracies. Further, information consumers are rational in the sense that they actively combine information from the mechanism with their sideinformation in a way that minimizes their loss. Under this assumption of rational behavior, we show that for every fixed count quer...