The term internet, spelled with a lower case "i," has always meant a large network made up of smaller networks. Today, the term mostly refers to the global Internet, properly spelled with an upper case "I" but increasingly written as lower case.
The global Internet comprises a billion Web, email and related servers in more than 100 countries. Originally developed for the U.S. military, it became widely used for academic and commercial research with access to unpublished data and journals on many subjects. As of 2019, more than three billion people use the Internet, and it has become indispensable to the world economy.
Not only is the "Net" the largest source of information on every subject known to humankind, it is also the greatest source of misinformation (unintentional) and disinformation (intentional falsehoods). The highest volume on the Internet is video traffic followed by everything else, including websites and Web apps, email, voice, chat, backup, app updating and machine-to-machine communications.
Email Lit the Fuse
In the mid-1990s, the Internet surged in growth, increasing a hundredfold in 1995 and 1996 alone. The first reason was email. Up to that point, the major online services, such as AOL and CompuServe, provided email only to their respective customers. As they began to reach out to Internet users by interfacing with the Internet's mail system, the Internet took on the role of a global email gateway. For the first time, an AOL member could send messages to a CompuServe member, and vice versa. The Internet glued the world together for email, and every service eventually switched to the Internet's own mail protocol (see SMTP
The Bomb Exploded with the Web
Secondly, with the advent of graphics-based Web browsers such as Mosaic and Netscape Navigator and Microsoft's Internet Explorer close behind, the World Wide Web took off. The Web became available to users with PCs and Macs rather than only to scientists and programmers at Unix workstations. Delphi was the first proprietary online service to offer Web access, and the others followed. Coming out of the woodwork, Internet service providers (ISPs) offered access to everyone, and the Web grew exponentially, soon becoming the majority of Internet traffic. Later, video streaming superseded Web pages as the dominant data traversing the Internet. See ISP
Although daily news and information is available on countless websites, long before the Web, information on myriad subjects was exchanged via the User Network newsgroups (see Usenet
). Still around, newsgroup articles can be selected and read directly from a Web browser.
Chat rooms provide another popular Internet service. Internet Relay Chat (see IRC
) offers multiuser text conferencing on diverse topics. Dozens of IRC servers provide hundreds of channels that anyone can log in to and participate via the keyboard.
The Original Internet
The Internet started in 1969 as the ARPAnet
. Funded by the U.S. government, ARPAnet became a series of high-speed links between major supercomputer sites and educational and research institutions worldwide, although mostly in the U.S. A major part of its backbone was the National Science Foundation's NSFNet. Along the way, it became known as the "Internet" or simply "the Net." By the 1990s, so many networks had become part of it and so much traffic was not educational or pure research in nature that it became obvious that the Internet was on its way to becoming a commercial venture.
It Went Commercial in 1995
In 1995, the Internet was turned over to large commercial Internet providers (ISPs), such as MCI, Sprint and UUNET, which took responsibility for the backbones and have increasingly enhanced their capacities ever since. Regional ISPs link into these backbones to provide lines for their subscribers, and smaller ISPs hook either directly into the national backbones or into the regional ISPs.
The TCP/IP Protocol
Internet computers use the TCP/IP communications protocol. An Internet server, no matter its size, is a "host" and always online via TCP/IP, providing email, Web and other services. In the past, the Internet was connected to non-TCP/IP networks through gateways that converted TCP/IP into other protocols. See TCP/IP
Access Was Command Driven in the Past
Before the Web and graphics-based Web browsers, academicians and scientists accessed the Internet using command-driven Unix utilities. Some of these utilities are still widely used for all platforms. For example, FTP (file transfer program) is used to upload and download files, and Telnet lets a user log in to a host and run a program. See FTP
The Next Internet
Ironically, some of the original academic and scientific users of the Internet have developed their own Internet once again. Internet2 is a high-speed academic research network that was started in much the same fashion as the original Internet (see Internet2
). See Web vs. Internet
, Internet of Things
, World Wide Web
, how to search the Web
, hot topics and trends
, information superhighway
and online service
These four nodes were drawn in 1969 showing the University of California at Berkeley and Los Angeles, SRI International and the University of Utah. This modest network diagram was the beginning of the ARPAnet and eventually the Internet. (Image courtesy of The Computer History Museum, www.computerhistory.org)
How the Internet Is Connected
Small Internet service providers (ISPs) hook into regional ISPs, which link into major backbones that traverse the U.S. This diagram is conceptual because ISPs often span county and state lines.