The World Wide Web
Many people assume that the World Wide Web is synonymous with the Internet. The two are not, however, the same thing.
Webopedia.com offers the following useful description of what sets the Web apart from the Internet:
"The World Wide Web, or simply Web, is a way of accessing information over the medium of the Internet. It is an information-sharing model that is built on top of the Internet. The Web uses the HTTP protocol, only one of the languages spoken over the Internet, to transmit data. Web services, which use HTTP to allow applications to communicate in order to exchange business logic, use the Web to share information. The Web also utilizes browsers, such as Internet Explorer or Netscape, to access Web documents called Web pages that are linked to each other via hyperlinks. Web documents also contain graphics, sounds, text, and video. The Web is just one of the ways that information can be disseminated over the Internet. The Internet, not the Web, is also used for e-mail, which relies on SMTP, Usenet news groups, instant messaging and FTP. So the Web is just a portion of the Internet, albeit a large portion, but the two terms are not synonymous and should not be confused." http://www.webopedia.com/DidYouKnow/Internet/2002/Web_vs_Internet.asp
Webopedia.com also gives a stand-alone definition of the World Wide Web:
"World Wide Web. A system of Internet servers that support specially formatted documents. The documents are formatted in a script called HTML (HyperText Markup Language) that supports links to other documents, as well as graphics, audio, and video files. This means you can jump from one document to another simply by clicking on hot spots. Not all Internet servers are part of the World Wide Web. There are several applications called Web browsers that make it easy to access the World Wide Web; Two of the most popular being Netscape Navigator and Microsoft's Internet Explorer."
When you use a program like Microsoft Outlook to send and receive e-mail, you are not actually using the World Wide Web (since, you are not using a Web browser to visit HTML formatted Web pages). The same thing applies to the use of file-sharing programs like Kazaa: the program itself makes use of the Internet to search for and transfer files from other computers, but it does not make use of any Web sites. It used to be that the URLs of most Web sites began with the letters "www," which of course stood for "World Wide Web." Today many Web sites do not use "www" in their addresses since it isn't really necessary. Suffice it to say, if you are using a Web browser like Navigator or Explorer, then you are surfing the World Wide Web.