U MIGHT HAVE SEEN A POPUP ON UER DESKTOP SCREEN " 1 UNREAD MESSAGE " OR " E-MAIL RECEIVED " A MILLION TIMES .
ANY CLUE " How does the e-mail notification work ??? "
HERE IS THE ANSWER >>>>

Several web browsers have extensions or options that let people know when E-MAIL is waiting in one or more of their inboxes. Other e-mail notification programs run independently and display a message or icon when e-mail arrives. But how do these programs work?
E-mail notification programs are very similar to the clients commonly used to send and receive e-mail. The difference is that e-mail notification applications are written specifically to check and report whether any new mail is on the server. Some programs allow people to read and even answer their mail, and others simply display a link that connects people to a web mail interface. In general, however, e-mail notification programs don't have the ability to save mail to disk or to organize messages into folders
Here's how most e-mail notification programs work:
1. The user configures the program with usernames and passwords from web mail (like Gmail or Yahoo! Mail), POST OFFICE PROTOCOL (POP3) or INTERNET MESSAGE ACCESS PROTOCOL (IMAP) accounts, depending on what the program supports.
2.When running, the program periodically contacts the server to see if any new mail has arrived. Most programs check the server every few minutes or at the interval the user specifies. They don't typically keep a constant connection to the server.
3.When new mail arrives, the program lets the user know by displaying a message or changing the shape of its icon
Different programs have different capabilities -- some allow users to read the message through the notification program, while others simply give the alert that the message is there. Not every program is compatible with every e-mail type -- some support only specific web mail clients, some only check POP3 servers and some support a range of web mail services as well as POP3 and IMAP services
so now u may think " WAT IS POP 3 ??? "
In the simplest implementations of POP3, the server really does maintain a collection of text files -- one for each e-mail account. When a message arrives, the POP3 server simply appends it to the bottom of the recipient's file!
When you check your e-mail, your e-mail client connects to the POP3 server using port 110. The POP3 server requires an account name and a password. Once you have logged in, the POP3 server opens your text file and allows you to access it. Like the SMTP server, the POP3 server understands a very simple set of text commands. Here are the most common commands:
USER - enter your user ID
PASS - enter your password
QUIT - quit the POP3 server
LIST - list the messages and their size
RETR - retrieve a message, pass it a message number
DELE - delete a message, pass it a message number
TOP - show the top x lines of a message, pass it a message number and the number of lines
Your e-mail client connects to the POP3 server and issues a series of commands to bring copies of your e-mail messages to your local machine. Generally, it will then delete the messages from the server (unless you've told the e-mail client not to).
You can see that the POP3 server simply acts as an interface between the e-mail client and the text file containing your messages. And again, you can see that the POP3 server is extremely simple!
SO NOW " WAT IS IMAP ??? "
As you can see, the POP3 protocol is very simple. It allows you to have a collection of messages stored in a text file on the server. Your e-mail client (e.g. Outlook Express) can connect to your POP3 e-mail server and download the messages from the POP3 text file onto your PC. That is about all that you can do with POP3.
Many users want to do far more than that with their e-mail, and they want their e-mail to remain on the server. The main reason for keeping your e-mail on the server is to allow users to connect from a variety of machines. With POP3, once you download your e-mail it is stuck on the machine to which you downloaded it. If you want to read your e-mail both on your desktop machine and your laptop (depending on whether you are working in the office or on the road), POP3 makes life difficult.
IMAP (Internet Mail Access Protocol) is a more advanced protocol that solves these problems. With IMAP, your mail stays on the e-mail server. You can organize your mail into folders, and all the folders live on the server as well. When you search your e-mail, the search occurs on the server machine, rather than on your machine. This approach makes it extremely easy for you to access your e-mail from any machine, and regardless of which machine you use, you have access to all of your mail in all of your folders.
Your e-mail client connects to the IMAP server using port 143. The e-mail client then issues a set of text commands that allow it to do things like list all the folders on the server, list all the message headers in a folder, get a specific e-mail message from the server, delete messages on the server or search through all of the e-mails on the server
One problem that can arise with IMAP involves this simple question: ?If all of my e-mail is stored on the server, then how can I read my mail if I am not connected to the Internet?? To solve this problem, most e-mail clients have some way to cache e-mail on the local machine. For example, the client will download all the messages and store their complete contents on the local machine (just like it would if it were talking to a POP3 server). The messages still exist on the IMAP server, but you now have copies on your machine. This allows you to read and reply to e-mail even if you have no connection to the Internet. The next time you establish a connection, you download all the new messages you received while disconnected and send all the mail that you wrote while disconnected.



- SRIKANTH DHANWADA
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SD
Hardwaredude.com Team