II · THE DISCOVERY · HISTORY OF SCIENCE
World Wide Web
Before the Web, the Internet existed but using it meant knowing commands and addresses. The Web made it possible to click from one document to another, anywhere in the world.
At a glance
- Invented
- 12 March 1989
- Credited to
- Tim Berners-Lee and Robert Cailliau
- Type
- Hypertext system and information system
- Status
- Credit is contested
Look closer
The Web is not the Internet
The Internet is the network of connected computers. The Web is a system that runs on top of it — a way of organising and linking documents so that one can lead to another. You use the Internet to send email or transfer files; you use the Web when you follow a link in a browser. The Web made the Internet usable for people who did not want to learn commands.
Hypertext means linked text
A hypertext system is one where documents contain links to other documents. Click a link and you jump to another resource, which might be on the same machine or a different one thousands of miles away. The Web is a hypertext system that works across the Internet, using a protocol — a set of rules — called HTTP to fetch documents, and a markup language called HTML to format them and embed the links.
The credit is contested
The facts record that credit for inventing the Web goes to Tim Berners-Lee and Robert Cailliau, and that this credit is contested. The record does not say what the contest is, or who else has a claim, only that the attribution is not settled. Berners-Lee is named in most accounts as the inventor; Cailliau is credited alongside him here, and the contested flag means the question of who did what is not closed.
The story
The World Wide Web is a system for linking documents across computers. It was invented on 12 March 1989, and credit goes to Tim Berners-Lee and Robert Cailliau, though that credit is contested.
The Web is not the same thing as the Internet. The Internet is the network itself — the physical and logical infrastructure that connects machines. The Web is a layer on top of it: a way of organising information so that documents on one machine can link to documents on another. Before the Web, the Internet existed and people used it, but accessing information meant knowing commands, addresses, and often the specific software for each kind of resource. The Web made it possible to click from one document to another without needing to know where the document lived or how to ask for it.
The mechanism depends on three pieces. A uniform resource locator, or URL, is a string of characters that identifies where a resource is and how to reach it. The Hypertext Transfer Protocol, or HTTP, is the set of rules computers follow to request and deliver those resources. Hypertext Markup Language, or HTML, is the format used to write web pages, which can include plain text, images, video, audio, and — crucially — hyperlinks, which are embedded URLs that let you jump to another resource when you click them. A web browser is the program that requests documents using HTTP, interprets the HTML, and displays the result.
A website is a collection of related web resources, usually sharing a domain name. A single web server can host multiple websites, and a single website can be served by multiple machines. The Web was opened to the public in 1993. It was conceived as a universal linked information system, and it has become the dominant way people interact with the Internet.
The facts record that the invention is credited to Tim Berners-Lee, who was working at CERN, and Robert Cailliau, and that this credit is contested. The record does not describe the nature of the contest or name other claimants, only that the question of who invented the Web is not settled.
Why it mattered then
Before the Web, the Internet was a network used mostly by researchers, and using it required technical knowledge. You had to know commands, protocols, and often the exact address of the resource you wanted. Different kinds of information required different tools. The Web changed that by making access uniform: every resource had a URL, every request used HTTP, and every link worked the same way. Click and the document arrived, whether it was on a machine next door or across an ocean. The Web was conceived as a universal linked information system, and opening it to the public in 1993 made that universality real. Institutions, companies, and individuals could publish documents that anyone with a browser could read, and those documents could link to each other without coordination. A page written in one country could point to a resource in another, and the system handled the rest. The Web made the Internet into something non-specialists could use, and use without training.
Why it matters now
The Web is now the primary tool that billions of people use to interact with the Internet. It is the platform for email clients, social networks, video streaming, banking, shopping, government services, and search engines. Most of what people think of as the Internet is actually the Web — pages and applications delivered through browsers. The structure Berners-Lee and Cailliau built is still in place. URLs still identify resources, HTTP still transfers them, HTML still formats pages, and hyperlinks still connect one document to another. The scale has changed — websites can be served by thousands of machines, and a single page can pull resources from dozens of different servers — but the mechanism is the same. The Web has become the world's dominant information system, and almost every digital interaction people have with institutions, media, and each other passes through it.
The surprising detail
The Web was invented at CERN, the European particle physics laboratory, and it was conceived as a tool for scientists to share information. The problem it was meant to solve was narrow: researchers at CERN were using different computers, different file systems, and different documentation formats, and there was no single way to find or link to information across those systems. The Web was designed to fix that, and it did. What is surprising is not that it worked, but that a tool designed for physicists turned out to be general enough to become the platform for almost everything people now do on the Internet. The universality was intentional — the name includes the word universal — but the scale of what rests on it now was not foreseen.
What is disputed
The facts record that credit for inventing the Web goes to Tim Berners-Lee and Robert Cailliau, and that this credit is contested. The record does not describe the nature of the dispute, name other claimants, or indicate what aspect of the invention is contested. Most accounts name Berners-Lee as the inventor; Cailliau is credited here alongside him, and the contested flag means the attribution is not settled.
Remember this
The Web made the Internet usable by turning access into something uniform: every resource had an address, every link worked the same way, and no special knowledge was required.
Test yourself
The Web was invented in 1989 and opened to the public in 1993, but the Internet existed before either of those dates. What did the Web add that the Internet alone did not have?
A uniform way to link documents across machines. The Internet was the network, but using it meant knowing commands and protocols that varied depending on what you were trying to reach. The Web introduced URLs to identify resources, HTTP to request them, HTML to format them, and hyperlinks to connect them. That made it possible to click from one document to another without needing to know where it was hosted or how to ask for it. The Web turned the Internet into something non-specialists could navigate.
Go deeper
Image: Raimundo Pastor, CC BY-SA 4.0. Licence: CC BY-SA 4.0. Source.