The world has a huge appetite for wireless video, voice, and data transmissions. And for American Tower Corp., the strategy is global. The Boston holding company owns and operates more than 50,000 wireless communications sites. For the first three quarters of 2012, revenue rose 17.7% to $2.1 billion; operating income rose 25% to $840.5 million. CEO Jim Taiclet credits “disciplined investments in portfolio growth and industry-leading operational efficiency.”