Difference Between Internet and World Wide Web

Can someone explain the difference between the Internet and the World Wide Web? Thank you

The internet is the sum of all the machines which can communicate with each other using the various internet protocols. The world wide web is just one "application" which runs on the internet "platform". Other popular internet applications include email, instant messaging (ICQ, AIM, Jabber etc.), file transfers using FTP, logging on to remote machines using telnet or ssh, peer-to-peer file sharing via napster or whatever, DNS lookups to find machine addresses and so on and so on. Anyone is free to produce or use any software which uses the internet protocols and all of these have nothing to do with the world wide web.

Thank you, Frank. So it's the application that runs on port 80 using the HTTP protocol. That's what I suspected. So are you implying that if I access an FTP application on a web server(port 21) via a browser(by typing in the FTP URL) that it's not on the world wide web? I've seen URLs that start with FTP, and other URLs. These servers are not on the world wide web? Then what are they? Thanks, Stan

The reason most browsers support "ftp:" URLs and have built-in mail and news clients is that they have to, because there are so many "applications" of the internet out there and browser competition is harsh. Just because you can access something using a commodity browser doesn't mean that it is the WWW. That's reserved for fetching documents using the HTTP and HTTPS protocols, and interpreting the result as HTML.
Your browser probably also implements clients for systems which were there before the web, like WAIS and Gopher, but nobody really uses these any more.

Thanks very much for you thorough explanations. They have been helpful.

Originally posted by Stan Levine:
Thank you, Frank. So it's the application that runs on port 80 using the HTTP protocol. That's what I suspected. So are you implying that if I access an FTP application on a web server(port 21) via a browser(by typing in the FTP URL) that it's not on the world wide web? I've seen URLs that start with FTP, and other URLs. These servers are not on the world wide web? Then what are they? Thanks, Stan