In an article for The Motley Fool, reporter Daniel Kline writes about the decline in exclusivity to membership-only retailers, like Costco and Sam’s Club, which has a strong correlation to the fact that nearly 50% of U.S. households will be enrolled as Amazon Prime members by the end of the year. Clarus Commerce CEO Tom Caporaso says that membership-only retailers shouldn’t panic, as there are many strategies they can follow to increase loyalty.