Speaking at the Goldman Sachs Communacopia XIX Conference, AT&T CEO Randall Stephenson said about half a million iPad owners use AT&T’s data service to connect to the internet, according to a Reuters report. AT&T is the only U.S. carrier currently offering cellular data service for the iPad with Wi-Fi + 3G; Apple said it sold 3.27 million iPads—a number that includes both 3G and Wi-Fi only models—in the second quarter…
