This research attempts to understand the mechanisms underlying the differential impacts of online consumer reviews, using the concept of cognitive personalization. In two experiments, the authors show that the level of cognitive personalization developed while reading an online review influences consumers' purchase intentions. The level of cognitive personalization is a function of the reader's affect intensity, the nature of the product reviewed (experience vs. search), and the content of the review (experiential vs. factual); in addition, the effect of cognitive personalization on purchase intention is moderated by valence (positive vs. negative).