IDC forecasts the number of worldwide wireless subscribers and customers to grow by a little more than a bln over the next four years, generating $800 bln in global wireless service revenue by 2011. IDC expects mobile entertainment will account for 5.1% of this total revenue and 23% of all mobile data revenue. The vast majority of this mobile entertainment revenue will be derived from ringtones, ringback tones, and mobile television and video services. Although there are significant regional differences, worldwide revenue and subscriber and customer totals are poised to increase at least 25% annually between 2006 and 2011.