The Internet
The Internet is the worldwide network of interconnected computer networks that exchange data using the TCP/IP protocol suite. It grew out of ARPANET, a U.S. research network whose first host-to-host message — the truncated word “lo” — was sent on 29 October 1969, and it expanded through packet switching, the Cerf–Kahn TCP protocols, the Domain Name System, and open standards bodies such as the IETF. Running on top of it is the World Wide Web, the hypertext information system invented by Tim Berners-Lee at CERN in 1989–1991 — a distinction this article keeps front and centre. By ITU estimates, about 6 billion people, or 74% of the world's population, were using the Internet in 2025.