Avnish Namdev

The World Wide Web is a system of interlinked, hypertext documents that runs over the Internet.
Or
The World Wide Web, abbreviated as WWW and W3 and commonly known as The Web, is a system of interlinked hypertext documents contained on the Internet.

With a web browser, one can view web pages that may contain text, images, videos, and other multimedia and navigate between them using hyperlinks.

The World Wide Web (“WWW” or simply the “Web”) is a global information medium which users can read and write via computers connected to the Internet. The term is often mistakenly used as a synonym for the Internet itself, but the Web is a service that operates over the Internet, as e-mail does. The history of the Internet dates back significantly further than that of the World Wide Web.

What does W3 define?

• The idea of a boundless information world in which all items have a reference by which they can be retrieved;
• the address system (URL) which the project implemented to make this world possible, despite many different protocols;
• a network protocol (HTTP) used by native W3 servers giving performance and features not otherwise available;
• a markup language (HTML) which every W3 client is required to understand, and is used for the transmission of basic things such as text, menus and simple on-line help information across the net;
• the body of data available on the Internet using all or some of the preceding listed items.

Linking
Over time, many web resources pointed to by hyperlinks disappear, relocate, or are replaced with different content. This phenomenon is referred to in some circles as “link rot” and the hyperlinks affected by it are often called “dead links“. The ephemeral nature of the Web has prompted many efforts to archive web sites. The Internet Archive is one of the best-known efforts; it has been active since 1996.

WWW prefix
Many web addresses begin with www, because of the long-standing practice of naming Internet hosts (servers) according to the services they provide. So, the host name for a web server is often www as it is ftp for an FTP server, and news or nntp for a USENET news server etc. These host names then appear as DNS subdomain names, as in “www.example.com”.

Many web servers are set up such that both the domain by itself (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 two different web sites.

When a single word is typed into the address bar and the return key is pressed, some web browsers automatically try adding “www.” to the beginning of it and possibly “.com”, “.org” and “.net” at the end. For example, typing ‘apple‘ may resolve to http://www.apple.com/ and ‘openoffice‘ to http://www.openoffice.org.
This feature was beginning to be included in early versions of Mozilla Firefox (when it still had the working title ‘Firebird’) in early 2003.

The ‘http://’ or ‘https://’ part of web addresses does have meaning: These refer to Hypertext Transfer Protocol and to HTTP Secure and so define the communication protocol that will be used to request and receive the page and all its images and other resources. The HTTP network protocol is fundamental to the way the World Wide Web works, and the encryption involved in HTTPS adds an essential layer if confidential information such as passwords or bank details are to be exchanged over the public internet. Web browsers often prepend this ’scheme’ part to URLs too, if it is omitted. Despite this, Berners-Lee himself has admitted that the two ‘forward slashes’ (//) were in fact initially unnecessary[24]. In overview, RFC 2396 defined web URLs to have the following form: :// ?#. Here is for example the web server (like www.example.com), and identifies the web page. The web server processes the (which can be data sent via a form, e.g. terms sent to a search engine), and the returned page depends on it. Finally, is not sent to the web server. It identifies the portion of the page which the browser shows first.