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POP3, IMAP and Webmail
Email is such a vital part of everyday communication, for both business and personal use, that it can be incredibly frustrating when something gets in the way of you using it in the way you want. There are three main kinds of email system, and they each have their benefits and problems.
POP3 (standing for Post Office Protocol 3) is the most familiar email protocol to most people. The majority of internet service providers (ISPs) provide free POP3 email addresses to all their users, and most people use these free POP3 accounts with an email client such as Outlook Express, Mozilla Thunderbird, or Eudora.
POP3 emails are held on a remote server until they are retrieved by an email client. They are then downloaded and stored on the user's own hard drive. The main benefit of this is that emails can be viewed, edited and searched while the user is offline, but now that broadband internet access is virtually ubiquitous, this is not as much of an advantage as it used to be. Email clients usually offer more functionality than webmail services, such as rich text formatting. POP3 access to emails also tends to be faster than that of webmail services, and your mailbox is only limited by the size of your hard drive.
However, POP3 can cause some problems if you want to be able to view your email in locations other than your home computer. Depending on your personal settings and the availability of features for your POP3 mailbox, you might find that, when you log onto the webmail version of your mailbox, everything you have retrieved using POP3 has been deleted in your webmail account. This can be extremely frustrating. Likewise, emails you send from and receive to your webmail account (rather than via your POP3 client) might not be retrieved by your POP3 client.
Webmail services are email services which you access via a web browser. Examples include MSN Hotmail, Yahoo! Mail, and Google Mail (a.k.a. Gmail). The main benefit of using webmail is that it can easily be accessed on any computer with a web browser, even if it does not have an email client, or if you do not have permission to configure the email client to collect your mail. Most webmail accounts are free, although sometimes you can upgrade to a pro account which has a larger mailbox and extra features.
Some webmail offers POP3 access, most notably Gmail, whose POP3 settings are truly excellent. With Gmail, it's possible to tell your account to both allow your email client to retrieve messages, and to keep these messages in your webmail account, so that you can access everything at home and elsewhere. All your messages sent from webmail can be retrieved by your POP3 client. This means that you are truly mobile: you have all the benefits of POP3 at home, but can access your emails and send new mail efficiently elsewhere.
There are a few disadvantages to webmail. Your storage space is limited (although Yahoo! Mail is soon to launch a free unlimited mailbox), as are the features available. The rich text editing of some webmail services is very poor, and the ability to search your messages is not available with all webmail services.
IMAP (Internet Message Access Protocol) is a newer email protocol than POP3, and was designed to deal with some of the problems with this older protocol, which is very limited, particularly when using a mobile device or working in different locations.
The IMAP service allows the user to download just the headings of their emails so that they can choose which they need to download completely. By default, only this descriptive information is sent to the user initially, which can be invaluable for those on slow connections or using a mobile device with limited storage. The user can then decide which emails to download in full.
Mail is kept on the mail server and is only delivered to an email client when it is requested by the user. The user can also place folders on the server in which to organise their emails, rather than having to do this on their own computer.
IMAP also allows several people to access a mailbox, and permits users to search the server for terms rather than just emails on their own computers.
More benefits of IMAP can be found here.
The big problem with IMAP is that it is not yet supported very widely. Really, at the moment, it's best for businesses rather than individual users. IMAP is a very complicated protocol and there's a lot that can go wrong, particularly in terms of traffic on the server from people using up memory by performing large searches. +Problems are also caused by the fact that several users can access the same mailbox simultaneously.
By Iain Ford