Eisenhower can be credited with the development of a second network: the interstate highway system. He signed into law the Federal Aid Highway Act of 1956, which provided funding for the construction of high-speed divided highways that spanned the United States. The construction of the interstates was an impressive feat, but the roads were secondary to the services they made possible. Their worth was ultimately determined by the traffic they carried, which included families on their way to Disney World and goods on their way to stores. So too do we measure the internet by the traffic that it carries.
Some of the earliest traffic to appear on the internet consisted of transferred files, remote login sessions, email and chat, and messages that helped computers synchronize their clocks. Such services still travel across the internet to this day. But one particular service has come to dominate the modern internet: the web.
In the mid-1980s, a British computer scientist by the name of Tim Berners-Lee was hired by CERN, a research laboratory in Switzerland, to study ways of managing information. Berners-Lee envisioned a platform for organizing related scientific reports and distributing them over the internet. A report on this system would not just be isolated text. Rather, it would contain links to other reports it built upon. Text containing links to other documents was called hypertext, a term first introduced in a non-networked context in 1965.
Berners-Lee acquired a computer from NeXT, a company founded by Steve Jobs after being ousted from Apple, and set to work on implementing his vision. In 1990, he had developed the three foundational pieces of his system for networked hypertext: HTML, HTTP, and a web browser.
Documents are marked up with Hypertext Markup Language (HTML) to declare their structure. To distinguish the markup from the content, HTML commands are surrounded by angle brackets, as in <ul>, a command that declares the subsequent content to be an unordered list.
The command <ul> is an opening tag, marking the beginning of the list. The ending of the list is marked with the closing tag </ul>. As another example, the following quotation is recognized as a paragraph because it is sandwiched between an opening <p> tag and a closing </p> tag:
<p>"Respect was invented to cover the empty place where love should be," said Leo.</p>Only 17 tags were identified in the first HTML standard. The modern HTML5 standard defines more than 100, with only 10 of the original tags remaining.
HTML tags are not meant to be read by humans. Rather, they are annotations that influence how documents are displayed or rendered. The software that interprets the annotations and renders the content is a web browser. Berners-Lee implemented the first web browser and named it WorldWideWeb.
WorldWideWeb was written using Objective-C on a NeXT computer for the NeXT operating system. Berners-Lee developed the software relatively quickly with the help of an interface builder that would later become part of Apple's Xcode development environment.
The web browser runs on the computer of the human browsing the web. The browser and the user's computer are both sometimes referred to as the client.
HTML documents are generally stored on a centralized computer called a server. The clients and server are both connected to the internet. To standardize how a client requests and receives a web page, Berners-Lee invented the Hypertext Transfer protocol (HTTP). He implemented the first web server, which he named httpd. It ran an infinite loop that awaited requests. When a request was received, the requested document was located on the file system and sent back to the client.
HTML, WorldWideWeb, and HTTP formed the technological foundation of Berners-Lee's vision for a platform of networked hypertext. Essential to that vision, however, were other users across the internet. To encourage others to join the platform, Berners-Lee convinced CERN to release the specifications and source code freely to the world. Berners-Lee reflects on his decision to make the web an open platform:
Had the technology been proprietary, and in my total control, it would probably not have taken off. The decision to make the Web an open system was necessary for it to be universal. You can't propose that something be a universal space and at the same time keep control of it.