Reporting its first quarter fiscal results, AT&T today announced that it activated 4.3 million iPhones during the period. That number is substantially higher than the 3.6 million iPhones activated in the year-ago quarter, and accounted for 78 percent of overall smartphone sales. 21 percent of the iPhone customers were new to AT&T. The carrier also added 240,000 tablet customers during the period—roughly three-quarters of which were postpaid—but…
