The IMAP4rev1 protocol (Internet Message Access Protocol) allows access to messages in mail folders on a server. Unlike POP3, which is designed to download the mails and delete them from the server, the purpose of IMAP is to store all mails on the server to be able to access these mails from everywhere. Messages can be stored on the server, retrieved from there or moved between folders.
This plugin is currently mainly used by KMail, but you can also use it in any other KDE application that uses kioslave plugins.
For example in Konqueror, simply type
imap://firstname.lastname@example.org/ to get your IMAP
folders listed. You can then deal with the folders and mails like with folders
and files on a local file system.
IMAP URLs are defined in RFC 2192.
IMAPS is the IMAP protocol encrypted via SSL.