In this research, we use a game-theoretic model to examine personalization of information in a twodimensional product differentiation model, when consumers attach importance to preference fit as well as product quality. We report the equilibrium in terms of two factors: one, the extent of firms ex-ante horizontal differentiation; and two, the Quality-Fit (Q-F) Ratio, which measures the relative strength of consumer preferences on each dimension of product differentiation. Under different conditions, personalization adoption by one firm in a duopoly can be profitable for neither firm, one firm or both firms. We also highlight conditions under which investments in personalization and product quality can be complements or substitutes to each other. Finally, we show that different values of the Q-F Ratio can lead a competitor to respond to a firms personalization by either increasing investments in its own quality (aggressive response) or by reducing investments in its own...