AT&T, reporting its third fiscal quarter financial results, has revealed that it activated a 2.7 million iPhones during the period. According to the release, those 2.7 million iPhones represented over half of the 4.8 million smartphones sold by the company during the period, which ended September 30. By the end of the quarter, over half—52.6 percent—of the company’s 68.6 million postpaid subscribers were using smartphones, up…