Additional
Information: This is a collection of links to pages which explain various protocols related to email handling. If you're looking for mail software, go look in Computers:Software. This is for people interested in understanding how the mail system itself works.
Network Services and Applications Network Services and Applications: A series of lecture notes and slides from the Faculty of Informatics and Communication, Central Queensland University. Covers many mail protocols. (Mail) http://www.infocom.cqu.edu.au/Units/aut2000/85321/Resources/Lectures/2000/16/
Email Addressing FAQ Email Addressing FAQ: The user+box@host addressing FAQ. A discussion of what exactly is permissible and verifiable in an e-mail address. (Mail) http://faqs.org/faqs/mail/addressing/
Message Access Paradigms and Protocols Message Access Paradigms and Protocols: Provides extensive background and compares the Post Office Protocol (POP) with the Internet Message Access Protocol (IMAP). (Mail) ftp://ftp.cac.washington.edu/mail/imap.vs.pop
Internet Mail Consortium Internet Mail Consortium: Information about IMC and its members, all the Internet mail standards, and links to several IMC-hosted mailing lists. (Mail) http://www.imc.org/
Client-Server Mail Protocols FAQ Client-Server Mail Protocols FAQ: A brief summary of POP3, SMTP, and IMAP, including pointers to sources and frequently-asked-questions sites. (Mail) http://www.faqs.org/faqs/mail/mailclient-faq/
The IMAP Connection The IMAP Connection: University of Washington collection of IMAP documentation and resources. (Mail) http://www.imap.org
MIME Meta-FAQ MIME Meta-FAQ: comp.mail.mime meta-FAQ: Help for MIME problems. Pointers to information about Multipurpose Internet Mail Extensions and some answers to common problems with MIME. (Mail) http://www.faqs.org/faqs/mail/mime-faq/mime0/
Detailed Revision/Update of Message Standards Detailed Revision/Update of Message Standards: The charter of the DRUMS IETF working group. DRUMS works on clarifying, codifying, and extending existing Internet messaging standards. (Mail) http://www.ietf.org/html.charters/drums-charter.html