Networked computers first communicated with each other the same year men first walked on the moon. It was 1969, and the moon got all the attention.
The breaking down of data into "packets" that could be routed independently of others supplanted telephone-type circuits with a system that could use a link to communicate with more than one machine. The U.S. Defense Department's Advanced Research Projects Agency Network, the forerunner of the Internet, was the first functional packet-switching network.
Four connected universities — University of California at Los Angeles, Stanford, the University of California at Santa Barbara and the University of Utah — joined in a research system, and computer scientists began building what would become the Internet. ARPANET, the Defense Department project, was demonstrated to the press and public in 1972.
The first e-mail program was written that year. A streamlined networking standard called Internet Protocol — the now-familiar IP — was in place by the late 1970s, although fewer than 200 computers were on the network.
A domain-name service was created in 1984, allowing the organization of online sites. It's the one we still use, with the familiar .com, .org, .net, .edu and so on.
In 1991, computer scientist Tim Berners-Lee developed the World Wide Web with the hypertext format that allowed users to see documents on their screens without having to download them, and a new world dawned.
"I just had to take the hypertext idea and connect it to the Transmission Control Protocol and domain name system ideas and — ta-da! — the World Wide Web," Berners-Lee later explained.
Berners-Lee designed and built the first browser and editor and the first Web server. He built the first Web site and put it online on Aug. 6, 1991. It explained what the Web was and how people could get browsers and set up servers.
When the browser Mosaic opened the online world further in 1993, early users — scientists, hobbyists, computer geeks, tech-freaks, idealists — worried that commercialization of cyberspace would diminish creativity or curtail freedom of speech, an obsession that seems quaint in a dot-com world.
According to the nonprofit Internet Society, IP version 4 (IPv4) is expected to run out of room for new Web addresses by 2010 or 2011. The transition to IPv6, a replacement that's been in the wings for years, is now looming.
Sources: The Internet Society, www.isoc.org/internet/history/brief.shtml; DARPA (Defense Advanced Research Projects Agency), www.darpa.mil; Internet World Stats, www.internetworldstats.com/stats2.htm; Wikipedia; Project A.