the authors propose a quality–fit ratio to represent a consumer’s strength of preference for quality compared to his or her preference for product fit. they develop a game-theoretic duopoly model to analyze the competitive interaction of information personalization and product differentiation. they find that both firms have an incentive to personalize their products in equilibrium when the costs of providing quality and the costs of product misfits are low. Otherwise, as long as the effectiveness of product personalization reaches at least some threshold value, one firm personalizes while the other firm relies on standard product marketing. the resulting equilibrium is generally asymmetric in the sense that one firm’s personalization strategy does not necessarily guarantee a higher profit than the other firm, only a higher profit than the alternative of both firms not personalizing