AT&T CEO Randall Stephenson, talked candidly about the company’s plans for including Time Warner, at this week’s Goldman Sachs Communacopia Conference – talking about becoming an advertising superpower. He cited the 200 billion a year advertising impressions which the existing combination of AT&T and DirecTV carry, claiming that they brought in about 3 times as much per impression as the 750 billion which Time Warner sells every year. By using big data, the data that AT&T and DirecTV have about their customers and selling advertising mostly online and programmatically, he said he felt that all 1 trillion advertising impressions the combined companies would have post-merger, could yield a similar kind of revenue – potentially tripling the Time Warner ad revenue…