Although the World Wide Web rapidly found enthusiasts among skilled computer users, it didn't come into its own until appealing software for navigation emerged from a supercomputing center established at the University of Illinois by NSF. There, two young computer whizzes named Marc Andreessen and Eric Bina created a program called Mosaic, which made Web browsing so easy and graphically intuitive that a million copies of the software were downloaded across the Internet within a few months of its appearance in April 1993. The following year Andreessen helped form a company called Netscape to produce a commercial version of Mosaic. Other browsers soon followed, and staggering quantities of information moved onto servers: personal histories and governmental archives; job listings and offerings of merchandise; political tracts, artwork, and health information; financial news, electronic greeting cards, games, and uncountable other sorts of human knowledge, interest, and activity—with the whole indescribable maze changing constantly and growing exponentially.

By the end of the 20th century the Internet embraced some 300,000 networks stretching across the planet. Its fare traveled on optical fibers, cable television lines, and radio waves as well as telephone lines—and the traffic was doubling annually. Cell phones and other communication devices were joining computers in the vast weave. Some data are now being tagged in ways that allow Web sites to interact. What the future will bring is anyone's guess, but no one can fail to be amazed at the dynamism of networking. Vinton Cerf, one of the Internet's principal designers, says simply: "Revolutions like this don't come along very often."