Internet, a system architecture that has revolutionized communications and methods of commerce by allowing various computer networks around the world to interconnect. Sometimes referred to as a “network of networks,” the Internet emerged in the United States in the 1970s but did not become visible to the general public until the early 1990s. By 2020, approximately 4.5 billion people, or more than half of the world’s population, were estimated to have access to the Internet.

The Internet provides a capability so powerful and general that it can be used for almost any purpose that depends on information, and it is accessible by every individual who connects to one of its constituent networks. It supports human communication via social media, (e-mail), “chat rooms,” newsgroups, and audio and video transmission and allows people to work collaboratively at many different locations. It supports access to digital information by many applications, including the World Wide Web. The Internet has proved to be a spawning ground for a large and growing number of “e-businesses” that carry out most of their sales and services over the Internet. 

Early networks

The first computer networks were dedicated special-purpose systems such as SABRE (an airline reservation system) and AUTODIN I (a defense command-and-control system), both designed and implemented in the late 1950s and early 1960s.

Commercial packet networks were introduced in the 1970s, but these were designed principally to provide efficient access to remote computers by dedicated terminals. Briefly, they replaced long-distance modem connections with less-expensive “virtual” circuits over packet networks. 

Foundation of the Internet

The Internet resulted from the effort to connect various research networks in the United States and Europe. First, DARPA established a program to investigate the interconnection of “heterogeneous networks.” This program, called Internetting, was based on the newly introduced concept of open-architecture networking, in which networks with defined standard interfaces would be interconnected by “gateways.” 

In 1974 Vinten Cerf, then at Stanford Universities in California, and this author, then at DARPA, collaborated on a paper that first described such a protocol and system architecture—namely, the transmission control protocol (TCP), which enabled different types of machines on networks all over the world to route and assemble data packets. TCP, which originally included the Internet protocol (IP), a global addressing mechanism that allowed routers to get data packets to their ultimate destination, formed the TCP/IP standard, which was adopted by the US Department of defense in 1980.

By the 1980s other U.S. governmental bodies were heavily involved with networking, including the National Science Foundation (NSF), the Department of Energy, and the National Aeronautics and Space Research (NASA). While DARPA had played a seminal role in creating a small-scale version of the Internet among its researchers, NSF worked with DARPA to expand access to the entire scientific and academic community and to make TCP/IP the standard in all federally supported research networks. 

From the Internet’s origin in the early 1970s, control of it steadily devolved from government stewardship to private-sector participation and finally to private custody with government oversight and forbearance. Today a loosely structured group of several thousand interested individuals known as the Internet Engineering Task Force participates in a grassroots development process for Internet standards.

Commercial expansion

The rise of commercial Internet services and applications helped to fuel a rapid commercialization of the Internet. This phenomenon was the result of several other factors as well. One important factor was the introduction of the PC and the workstation in the early 1980s—a development that in turn was fuelled by unprecedented progress in integrated circuit technology and an attendant rapid decline in computer prices. Another factor, which took on increasing importance, was the emergence of Ethernet and other “local area networks” to link personal computers. But other forces were at work too. In 1988 the Corporation for National Research Initiatives received approval to conduct an experiment linking commercial e-mail services (MCI Mail) to the Internet. Approval quickly followed to allow other e-mail providers access, and the Internet began its first explosion in traffic.

Also in 1993, the University of Illinois made widely available Mosaic, a new type of computer program, known as a browser, that ran on most types of computers and, through its “point-and-click” interface, simplified access, retrieval, and display of files through the Internet. Mosaic incorporated a set of access protocols and display standards originally developed at the European Organization for Nuclear Research for a new Internet application called the WWW. These new commercial capabilities accelerated the growth of the Internet.

By the late 1990s, there were approximately 10,000 ISPs around the world. Widely used Internet “portals” such as AOL, Yahoo, Excite, and others were able to command advertising fees owing to the number of “eyeballs” that visited their sites. Indeed, during the late 1990s advertising revenue became the main quest of many Internet sites, some of which began to speculate by offering free or low-cost services of various kinds that were visually augmented with advertisements. By 2001 this speculative bubble had burst.

The 21st century and future directions

After the collapse of the Internet bubble came the emergence of what was called “Web 2.0,” an Internet with emphasis on social networking and content generated by users, and cloud computing. Social media services such as Facebook, Twitter, and Instagram became some of the most popular Internet sites by allowing users to share their own content with their friends and the wider world. Mobile phones became able to access the Web, and, with the introduction of smartphones like Apple’s iPhone (introduced in 2007), the number of Internet users worldwide exploded from about one-sixth of the world population in 2005 to more than half in 2020.

The increased availability of wireless access enabled applications that were previously uneconomical. For example, global positioning systems (GPS) combined with wireless Internet access help mobile users to locate alternate routes, generate precise accident reports and initiate recovery services, and improve traffic management and congestion control. In addition to smartphones, wireless laptop computers, and personal digital assistants (PDAs), wearable devices with voice input and special display glasses were developed.

The dissemination of the digitized text, pictures, and audio and video recordings over the Internet, primarily available today through the World Wide Web, has resulted in an information explosion. Clearly, powerful tools are needed to manage network-based information. The information available on the Internet today may not be available tomorrow without careful attention being paid to preservation and archiving techniques. The key to making information persistently available is infrastructure and the management of that infrastructure. Repositories of information, stored as digital objects, will soon populate the Internet. At first, these repositories may be dominated by digital objects specifically created and formatted for the World Wide Web, but in time they will contain objects of all kinds in formats that will be dynamically resolvable by users’ computers in real-time. The movement of digital objects from one repository to another will still leave them available to users who are authorized to access them, while replicated instances of objects in multiple repositories will provide alternatives to users who are better able to interact with certain parts of the Internet than with others. Information will have its own identity and, indeed, become a “first-class citizen” on the Internet.