The Federal Communications Commission recently gave mobile carriers the green light to expand zero-rating, a method of favoring online content by exempting it from data caps.

At the same time, carriers have been competing to offer the best unlimited data plans—and without data caps, there’s no need for zero-rating. But that doesn’t mean zero-rating and similar free data offers are over and done with, because many customers are still going to buy cheaper, limited data plans.

AT&T and Verizon seemed reluctant to make unlimited data plans widely available until they faced competitive pressure to do so. Those two carriers have created new sources of revenue by seeking payments from companies that want to bypass data caps in order to reach more customers.