With all the online promotions and email coupon offers, what are consumers getting when they shop online? MIT researchers found that retailers’ online prices are lower for 22 percent of items, while in-store prices were lower for just 8 percent of items; 70 percent of items were about the same price. When people shop online, retailers get something valuable — data about what kinds of things customers are buying and ways to adjust prices to encourage consumers to buy more.

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