Online advertising. Google’s main source of revenue is its advertising business. In 2014, advertising generated US$59 billion or 89.5% of the company’s total revenue. According to eMarketer,[2] Google earns more than 30% of the world’s digital advertising revenue, 4 times as much as the next largest earner, Facebook. The company dominates the digital advertising market through many different channels, including its own AdWords advertising program, AdSense, YouTube and the Android OS. By dominating the online advertising market Google can better understand current advertising trends, collect an enormous amount of information about online users’ shopping habits, and enhance their related services by improving targeted advertisements.