The ancestry of the Internet lies in the development of ARPANET (Advanced Research Projects Agency Network), funded by the U.S. Department of Defense, for use by its university contractors and research labs in the exchange of information. It soon became a critical piece of the infrastructure for the scientific research community in the United States; tools and applications - such as simple mail transfer protocol (commonly referred to as e-mail) and file transfer protocol (FTP) for longer transmission - were developed in short order.

In the early 1980s, the Defense Department adopted the privately-developed transmission control protocol (TCP), which enabled different makes of computers on networks to route and reassemble data packets anywhere in the world. Along with the internet protocol (IP), a global address system, the TCP "open architecture" approach was enthusiastically accepted by most researchers and businesses around the world.

Within a few years, the network was transferring millions of bits per second, and several commercial networks were flourishing. In 1993 the University of Illinois made freely available "Mosaic," a new type of program for a new Internet technology dubbed the "World Wide Web." Within a few months, a number of corporations such as Netscape and Microsoft had entered the exploding field with browser and server software for use on personal computers. By the late 1990s there were approximately 100,000 Internet service providers around the world. In the first decades of the new century, the Internet was expanding an estimated 100% annually, making it the greatest conduit for information and entertainment in world history.