CAIDA collects, monitors, analyzes, and visualizes several forms of Internet traffic data concerning network topology, workload characterization, performance, routing, and multicast behavior. http://www.caida.org/
Attempts to discover every host on the Internet by doing a complete search of the Domain Name System. Statistics available for free and commercially. http://www.isc.org/ds/
Historical and current information on the growth and trends in Internet usage. View of developing web demographics, culture, user attitudes, and usage patterns, advertising, electronic commerce, intranet web usage, and business-to-business transactions. http://www.cc.gatech.edu/gvu/user_surveys/