Internet giants such as Google and Facebook rely on advertising revenue to finance their various endeavors. However, that business model is now being threatened by ad-blocking software. According to a report from PageFair and Priori Data, about 20 percent of smartphone users (nearly 420 million people worldwide) now block ads when browsing online via their mobile devices. The latest figures represent a 90 percent annual increase. While the use of ad-blocking software conserves data and loads websites faster, it “is costing the global advertising industry billions of dollars a year in lost revenue,” reports The New York Times.