In its Q3 2013 earnings, AT&T announced that smartphones have continued to take over its postpaid network in a major way. Three quarters of its postpaid customers are now using smartphones — up from just 66 percent this quarter last year — and the company expects that this number will continue to grow. The carrier also sold more smartphones than ever before, selling 600,000 more year-over-year, with 89 percent of postpaid device sales being smartphones.

When asked about T-Mobile's newly announced plan to give tablet users 200MB of free data, AT&T CFO John Stephens dismissed concerns that it might be cutting into his business. "There continues to be a lot of noise about what's going on," Stephens says. "You have to realize that our [subscriber loss] was down year-over-year ... That's the real measure." Though AT&T has been reactive to T-Mobile's tactics, it seems that it hasn't been having a serious effect yet.