You search for a pair of running shoes, compare a few prices, leave the tab open, and come back later ready to buy. But what if the information collected during that process helps determine not only what products you see, but also the prices or discounts presented to you? That possibility is becoming more important as retailers use algorithms, loyalty data, browsing behavior and other consumer information to personalize online shopping. While personalized pricing does not mean every shopper is secretly charged a different price, recent research and regulatory scrutiny show that the practice deserves consumers’ attention.