Previously you could purchase as much as you wanted at stand alone grocery stores and get the 6% cash back bonus. As you may guess, many people were not only purchasing groceries at the grocery store, but they were purchasing gift cards as well. This enabled people to get not only 6% cash back on groceries, but also on the gift cards sold at the grocery stores (gas, food, clothing retailers, and even MasterCard/Visa/Amex gift cards).
The first $6,000 of eligible U.S. stand-alone supermarket purchases in a calendar year qualify for the 6% reward; 1% thereafter. Supermarkets exclude superstores and warehouse clubs