World Wide Web
The World Wide Web, also known as the WWW and the Web, is an information space where documents and other web resources are identified by Uniform Resource Locators (URLs), interlinked by hypertext links, and accessible via the Internet. English scientist Tim Berners-Lee invented the World Wide Web in 1989. He wrote the first web browser in 1990 while employed at CERN near Geneva, Switzerland. The browser was released outside CERN in 1991, first to other research institutions starting in January 1991 and to the general public on the Internet in August 1991.
World Wide Web
Many hostnames used for the World Wide Web begin with "www" because of the long-standing practice of naming Internet hosts according to the services they provide. The hostname of a web server is often "www", in the same way that it may be "ftp" for an FTP server, and "news" or "nntp" for a Usenet news server. These host names appear as Domain Name System (DNS) or subdomain names, as in "www.example.com". The use of "www" is not required by any technical or policy standard and many web sites do not use it; the first web server was "nxoc01.cern.ch". According to Paolo Palazzi, who worked at CERN along with Tim Berners-Lee, the popular use of "www" as subdomain was accidental; the World Wide Web project page was intended to be published at www.cern.ch while info.cern.ch was intended to be the CERN home page, however the DNS records were never switched, and the practice of prepending "www" to an institution's website domain name was subsequently copied. Many established websites still use the prefix, or they employ other subdomain names such as "www2", "secure" or "en" for special purposes. Many such web servers are set up so that both the main domain name (e.g., example.com) and the "www" subdomain (e.g., www.example.com) refer to the same site; others require one form or the other, or they may map to different web sites. The use of a subdomain name is useful for load balancing incoming web traffic by creating a CNAME record that points to a cluster of web servers. Since, currently, only a subdomain can be used in a CNAME, the same result cannot be achieved by using the bare domain root.