Internet service provider (ISP), company that provides Internet connections and services to individuals and organizations. ISPs may also provide software packages (such as browsers), e-mail accounts, and a personal website or home page. ISPs can host websites for businesses and can also build the websites themselves. ISPs are all connected to each other through network access points, public network facilities on the Internet backbone.

The rise of commercial Internet services and applications helped 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 personal computer (PC) and the workstation in the early 1980s—a development that in turn was fueled 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” (LANs) to link personal computers. But other forces were at work too. Following the restructuring of AT&T Corporation in 1984, the U.S. National Science Foundation took advantage of various new options for its national-level digital backbone service, known as NSFNET. In 1988 the U.S. Corporation for National Research Initiatives received approval to conduct an experiment linking a commercial e-mail service (MCI Mail) to the Internet. This application was the first Internet connection to a commercial provider that was not also part of the research community. Approval quickly followed to allow other e-mail providers access, and the Internet began its first explosion in traffic.

In 1993 federal legislation allowed NSF to open the NSFNET backbone to commercial users. Prior to that time, use of the backbone was subject to an “acceptable use” policy, established and administered by NSF, under which commercial use was limited to those applications that served the research community. NSF recognized that commercially supplied network services, now that they were available, would ultimately be far less expensive than continued funding of special-purpose network services.

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 (CERN) by Tim Berners-Lee for a new Internet application called the World Wide Web (WWW). In 1994 Netscape Communications Corporation (originally called Mosaic Communications Corporation) was formed to develop a Web browser, Netscape Navigator, and server software for commercial use. Shortly thereafter the software giant Microsoft Corporation became interested in supporting Internet applications on personal computers and developed its Internet Explorer Web browser (based initially on Mosaic) and other programs. These new commercial capabilities accelerated the growth of the Internet, which as early as 1988 had already been growing at the rate of 100 percent per year.

By the late 1990s there were approximately 10,000 ISPs around the world, more than half located in the United States. However, most of these ISPs provided only local service and relied on access to regional and national ISPs for wider connectivity. Consolidation began at the end of the decade, with many small to medium-sized providers merging or being acquired by larger ISPs. Among these larger providers were groups such as America Online, Inc. (AOL), which had started as a dial-up information service with no Internet connectivity but made a transition in the late 1990s to become the leading provider of Internet services in the world—with more than 25 million subscribers by 2000 and with branches in Australia, Europe, South America, and Asia. Meanwhile, many new state-owned ISPs entered the business in large national markets, such as China, India, and Indonesia, and quickly eclipsed the subscriber base of any traditional commercial ISP.

In the early 21st century, many dial-up Internet customers shifted to broadband service for faster Internet connections. The entry-level broadband service offered by telephone and cable television companies cost as little as dial-up services in some parts of the United States, and some companies bundled together telephone, cable television, and Internet service. As a result of the shift, dial-up Internet provider AOL watched its base of dial-up service subscribers decline from nearly 27 million in 2002 to 2.1 million in 2015. By 2020 more than 120 million households in the United States had broadband Internet.

With the proliferation of services such as Netflix that stream video and other large files, ISPs pushed for the right to offer differently priced tiers of service to online content or software providers on the basis of their Internet use. Proponents of net neutrality believe, among other things, that network providers should be required to treat all broadband consumers equally instead of charging some consumers higher prices for using more bandwidth (data-carrying capacity). Opponents of net neutrality question whether cable and telephone companies could afford to invest in advanced security or transmission services if they could not charge a premium for them. In general, big Internet providers of content and software supported net neutrality, while the ISPs were against it. In the United States, the Federal Communications Commission initially issued orders in favour of net neutrality in 2010 and 2015, but under the Trump administration those policies were reversed in 2017.

Are you a student?

Get a special academic rate on Britannica Premium.

Subscribe