When you log on to an online retailer, like Amazon, one of the first things you’ll see are recommendations for future purchases. If you purchased a certain brand of stroller, Amazon might suggest you take a look at the brand’s car seats, as well. Online retailers keep track of what you bought so that they know what you might like in the future, providing a more personalized shopping experience in the process. And no surprise - customers love this feature because it shortens the time it takes them to shop, and helps them shop more effectively.