Songwriter Dave Carroll wasn't the first person abused by an airline's customer service. But he was the first to show how one person, armed with creativity, some friends, $150, and the Internet, could turn an entire industry upside down. United Airlines had broken Dave's guitar in checked luggage. After eight months of pestering the company for compensation, he turned to his best tool--songwriting--and vowed to create a YouTube video about the incident that he hoped would garner a million views in one year. Four days after its launching, the first million people had watched "United Breaks...