Safari Books Online is a digital library providing on-demand subscription access to thousands of learning resources.
Europe has a mature mobile market and excellent cell phone coverage. Its networks are based on GSM, and consumers take the ability to use their cell phone throughout the continent for granted. The mature market combined with declining voice usage has resulted in a lower Average Revenue Per User (ARPU) and fewer opportunities for growth. To date, revenue from data usage has not made up for the decline in revenue from voice calling. At the same time that average revenues are declining, carriers are faced with the need to invest in spectrum and equipment for higher-generation data services that add capacity to networks. Despite lower revenues per user, most operators have robust operating margins because of recurring monthly subscription fees.