Before the internet: the packet switching idea
Early computer communications often resembled telephone systems, with a dedicated circuit reserved for a conversation. Researchers instead explored packet switching: dividing information into small blocks that could travel independently through a shared network and be reassembled at the destination. Work by Paul Baran in the United States, Donald Davies in the United Kingdom and others helped establish the concept.
1969: ARPANET comes online
The United States Advanced Research Projects Agency funded ARPANET to connect research computers. By the end of 1969, four nodes operated at UCLA, the Stanford Research Institute, UC Santa Barbara and the University of Utah. The system demonstrated that geographically separated, differently designed computers could share network resources.
ARPANET also helped establish a culture of open technical discussion. Steve Crocker issued the first Request for Comments, or RFC, in 1969. The deliberately informal series became the enduring record through which internet engineers propose, debate and document protocols.
1970s: connecting networks, not just computers
A single network could not serve every environment. Radio networks, satellite links and wired systems had different characteristics. Vint Cerf and Bob Kahn worked on an architecture in which these distinct networks could interconnect while retaining their internal design. The resulting Transmission Control Protocol and Internet Protocol separated reliable end to end delivery from the movement of packets across networks.
TCP/IP created a common layer between diverse networks. A new network did not need to copy every other network. It needed to speak the shared protocol.
1983: the TCP/IP transition
On 1 January 1983, ARPANET formally transitioned from its earlier Network Control Protocol to TCP/IP. This is often treated as a birthday of the operational internet. The Domain Name System followed in the 1980s, giving people a distributed way to use readable names instead of remembering numerical addresses.
1986 to 1995: NSFNET and wider access
The United States National Science Foundation launched NSFNET in 1986 to connect supercomputing centres and academic networks. According to the NSF, it connected around 2,000 computers in 1986 and more than two million by 1993. Regional networks and commercial providers multiplied. In 1995, the NSFNET backbone was decommissioned as commercial internet infrastructure took over.
1989 to 1993: the World Wide Web
At CERN, Tim Berners-Lee proposed a system for managing linked information in March 1989. Working with Robert Cailliau, he formalised the proposal in 1990 and built the first Web server, browser and website. The Web combined three foundational technologies: URLs for addressing resources, HTTP for transferring them and HTML for structuring linked documents.
On 30 April 1993, CERN made the Web software available on a royalty free basis. That decision removed a major barrier to adoption. Mosaic, developed at the US National Center for Supercomputing Applications, helped make graphical browsing accessible to a broader public.
Commercialisation, search and platforms
During the 1990s, commercial internet service providers expanded household access. Portals, search engines, online stores and webmail made the network useful to non specialists. Broadband later replaced slow dial up connections for many households. Search engines organised an exploding Web, while advertising became a central business model.
In the 2000s, participatory publishing, Wikipedia, blogs, video sharing and social networks made users creators as well as readers. Large platforms increasingly mediated discovery, identity, speech and commerce. Their scale produced enormous convenience and concentrated influence.
Mobile, cloud and the always connected world
Smartphones placed networked computers in billions of pockets. Wireless networks, app stores, cloud computing and content delivery networks made services available almost everywhere. The internet became less visible as a destination and more like an underlying condition of work, navigation, entertainment, finance and public life.
The story is not finished
Access remains unequal, IPv6 adoption continues, undersea cables and data centres keep expanding, and governance remains distributed among governments, firms, technical bodies and civil society. The internet is both a technical architecture and an evolving social settlement.