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Brief Overview: Web vs. Internet, Email
Last updated Oct 17, 2003.
The World Wide Web (WWW) plays a large part in the Internet. The two aren't interchangeable because the Internet is how the data flows between computers, it's the network and infrastructure. The WWW is the protocol, which sits on top of the infrastructure and integrates with it. View the Web as an interface, a term for a group of Web sites. Web sites have content in forms of text, audio, video, and pictures.
Tim Berners-Lee invented the Web, which integrates a Web site holding the information and a browser that interprets the information into the interface you see.
In reflecting on his WWW work, Tim Berners-Lee writes:
"The dream behind the Web is of a common information space in which we communicate by sharing information. Its universality is essential: the fact that a hypertext link can point to anything, be it personal, local or global, be it draft or highly polished. There was a second part of the dream, too, dependent on the Web being so generally used that it became a realistic mirror (or in fact the primary embodiment) of the ways in which we work and play and socialize. That was that once the state of our interactions was on line, we could then use computers to help us analyze it, make sense of what we are doing, where we individually fit in, and how we can better work together."
Though most of our emails are filled with annoying spam, phishes, recycled jokes, and urban legends, email has become a valuable tool that has changed the way millions communicate with one another. An email is a simple text message sent from one person to another via the Internet's network. Email is sent through its own protocol(s), which are on top of the Internet. An email client interprets the email message and puts it in the form you see when reading emails.
The process that occurs after clicking "Send" to send an email to another person looks complicated and yet it's disassembled and reassembled in seconds. Your email program breaks the email into packets of information based on Transmission Control Protocol (TCP) rules, which include instructions on how these packets should be handled. The email program connects with your ISP (Internet Service Provider) computer, which is the outgoing mail server also known as the SMTP (Simple Mail Transfer Protocol) server, a mail submission server.
The outgoing mail server reviews the email message and grabs the receiver's email address. Before arriving at its final destination, the email passes through a number of routers where these systems review the address in the packets of information and forward them closer to the email's intended destination. Typically, this system works to find the shortest route from point A to point B, but it's not always the case—because of "traffic jams." If a route is crowded and slow-moving, the email is routed to a different route.
When the email arrives at its destination, it comes through the incoming mail server, also known as Post Office Protocol version 3 (POP3—it's defined in http://www.ietf.org/rfc/rfc1939.txt">RFC 1939) or Internet Message Access Protocol version 4 (IMAP4—its most current is IMAP4rev1 and it's defined in http://www.ietf.org/rfc/rfc3501.txt">RFC 3501). Here, the packets of information are reassembled and the email arrives into the email box waiting for someone to open it and read it. IMAP4 is a redesigned POP3 and has more features than POP3.
Why don't more people use IMAP instead of POP? Its additional features cost more, it uses more CPU resources, and it requires more server space. Webmail provides a user with access to his email through the Web browser using HTTP or HTTPS. All three have differences, but they share the ultimate goal of receiving email.
Simply put, POP3 and IMAP4 receive email while SMTP sends email. Amazing how the Internet handles billions of these every day with a tiny percentage of errors.