IMAP4
IMAP4 is a mail protocol that allows users to be disconnected from the main messaging
system and still be able to process mail. Users can store messages on a local machine
or on a server.
IMAP has distinct advantages over POP because it allows you manage multiple folders
on the server. Mail can be accessed from different machines, as the mail is hosted
on the server (unlike POP which deletes mail from the server after being accessed)
and allows the user to just download message headers and envelope information, until
the user selects the email to download. This is useful when operating over slow
speed dial-up connections.
IMAP4 can break up and download specific parts of a multi-part email message (MIME).
This means that instead of having to wait for an email with attachments to download,
you can select only the text portion to download, and leave the attachments on the
server.
IMAP4 allows you to have server hosted folders and subfolders.
HTTPMail
HTTPMail is a mail access protocol that allows you to access your mail from the
server and leaves the email on the server. HTTPMail provides similar functionality
to IMAP, where by an Outlook Express or Outlook client can access and manage messages
and folders on the server. Unlike IMAP, it does not require SMTP to send messages.
Another advantage that HTTPMail has over using POP and SMTP is that it can be configured
to operate over Port 80, meaning that you can access your mail through corporate
firewalls.
POP3
Post Office Protocol. This is a mail protocol that enables emails to be retrieved
from a remote mailbox. That is, it allows you to collect emails from an hosted account
that you have hosted on a server to your own email software, such as Outlook, Eudora
etc.