From ARPANET's First Packet to a 6-Billion-User Internet: A Timeline

The global network now called the internet did not start as a consumer product. It grew out of a U.S. government research project in the late 1960s, was rebuilt on a common technical standard in the 1980s, and only became the point-and-click 'Web' that most people recognize after a proposal written at a European physics laboratory in 1989.

ARPANET: the Cold War-era starting point

According to the U.S. Defense Advanced Research Projects Agency (DARPA), ARPANET was created in the late 1960s under program manager J.C.R. Licklider to allow secure communication and information-sharing between geographically dispersed research facilities. The network began with four nodes: UCLA, the Stanford Research Institute, UC Santa Barbara and the University of Utah.

The first signal between two of those nodes was transmitted on October 29, 1969, according to DARPA's log of the event. A UCLA researcher attempted to type the word 'login' on a computer connected to a machine at the Stanford Research Institute, but the system crashed after only the letters 'L' and 'O' went through, according to History.com's account of the day. UCLA professor Leonard Kleinrock had been developing packet switching — breaking data into small blocks that could be reassembled after transmission — which History.com and DARPA describe as the foundational technique that made the network, and later the internet, resistant to single points of failure.

TCP/IP and the 1983 'flag day'

By 1973, researchers had built several competing packet-switching systems, DARPA notes. Vint Cerf and Robert Kahn then designed the Transmission Control Protocol and Internet Protocol (TCP/IP), a shared language that let separate networks interconnect. The first TCP/IP implementation ran at Stanford in 1975.

The Internet Society's history of the project describes January 1, 1983, as a 'flag day': every host on ARPANET had to switch from the older NCP protocol to TCP/IP simultaneously. DARPA states that by January 1983 enough separate networks had interconnected using this protocol that ARPANET had, in effect, become the internet. TCP/IP had also been adopted as a U.S. defense standard in 1980, and by 1990 it had displaced most rival wide-area networking protocols worldwide, per the Internet Society.

NSFNET and the spread beyond the military

The U.S. National Science Foundation built on this foundation with NSFNET, established in 1985 and requiring TCP/IP from the start, according to the Internet Society. The backbone grew from six 56-kilobit-per-second links to 21 nodes carrying multiple 45-megabit-per-second connections before it was defunded in April 1995, at which point its resources were redistributed to regional networks supporting commercial internet access. By 1990, the Internet Society says, more than 50,000 networks existed across all seven continents, while ARPANET itself was formally decommissioned that same year.

The World Wide Web: a 1989 proposal at CERN

The internet and the World Wide Web are not the same thing: the internet is the underlying network, while the Web is a system of linked documents that runs on top of it. According to CERN, British scientist Tim Berners-Lee drafted the first proposal for the Web in March 1989 while working at the Geneva-based laboratory. He resubmitted it in 1990 and, with Belgian engineer Robert Cailliau, formalized it as a management proposal in November 1990.

By the end of 1990, Berners-Lee had a working server and browser on a NeXT computer at CERN, which he marked with a handwritten warning not to switch it off. CERN says the first website, info.cern.ch, went live around this time, and the software was shared with CERN colleagues in March 1991 before Berners-Lee announced it publicly on Internet newsgroups in August 1991. A pivotal moment for adoption came on April 30, 1993, when CERN made the WorldWideWeb source code available on a royalty-free basis, making it free software.

From dial-up to 6 billion users

Commercial internet service grew through the 1990s as NSFNET's federal backbone wound down and private providers took over. Decades later, the United Nations' International Telecommunication Union (ITU) estimates that about 6 billion people — roughly three-quarters of the world's population — were using the internet in 2025. The ITU says 2.2 billion people remained offline in 2025, down from a revised 2.3 billion in 2024.

Access remains uneven. The ITU reports that 94% of people in high-income countries use the internet, compared with 23% in low-income countries, and that 96% of the world's offline population lives in low- and middle-income countries. Urban users (85% online) significantly outnumber rural users (58% online), and the ITU also records a gender gap of 77% of men online versus 71% of women globally.

On mobile networks, the ITU says 5G subscriptions reached roughly 3 billion in 2025, about one-third of all mobile broadband connections, but with sharply unequal coverage: 84% of people in high-income countries have 5G access versus 4% in low-income countries. The ITU adds that users in high-income countries generate nearly eight times more mobile data than those in low-income countries.