of data. In addition to increased revenue, apps are making it more complex for custom- ers to change carriers. Customers often find it simpler to remain with their carrier SO that they don't have to repurchase their apps. In recent years AT&T and Verizon have had lower churn rates. This refers to the percentage of customers that change carriers annually. Lower churn rates result in savings on customer service for activating new customers and deactivating former customers' accounts. Industry Consolidation Until mid-2004, there were six major mobile carriers in the United States: AT&T Mobility, Verizon Wireless, Cingular, Sprint, Nextel, and T-Mobile USA. In 2004, Cin- gular purchased AT&T Wireless and changed the Cingular name to AT&T Mobility. In 2005, Sprint merged with Nextel, bringing the number down to four large mobile providers. Table 3-4 lists the largest facilities-based mobile carriers. Industry consolidation that results in near-monopoly conditions has ramifications for customers as well as competitors. For customers, it can mean higher prices and less innovation. This is because monopolies have few incentives to be competitive with regard to prices or develop new features to attract customers. Smaller mobile competitors suffer the disadvantage of higher operating costs. For example, large carriers have the clout to bargain for discounts on quantity purchases of cell phones and network equipment. These discounts are often unavailable to small carriers. Another disadvantage is that smaller providers don't have the resources to mount large TV and Internet advertising campaigns; thus, it's more difficult to attract new customers. In addition to the resources to launch broader advertising campaigns, large mobile carriers have the financial strength to lease spectrum needed for additional capacity and next-generation data networks. In the 2008 FCC spectrum auction, Verizon and AT&T's combined bids were $12.8 billion; that was 67 percent of the $19 billion that was bid in total at the auction. This spectrum i