New York–Online catalogers are facing a new challenge: comparison shopping engines (CSEs), which enable customers to compare pricing, fulfillment, and other information about a specific product sold by multiple Websites. According to a recent study by direct marketing research firm The Winterberry Group, CSEs are expected to influence nearly 10% of business-to-consumer e-commerce dollars, or $25 billion out of a total $278 billion b-to-c e-commerce market.