* Message headers fields.

  from            =       "From:" mailbox-list CRLF

  sender          =       "Sender:" mailbox CRLF

  reply-to        =       "Reply-To:" address-list CRLF

  to              =       "To:" address-list CRLF

  cc              =       "Cc:" address-list CRLF

  bcc             =       "Bcc:" (address-list / [CFWS]) CRLF

  newsgroups

  http://tools.ietf.org/rfc//rfc2076.txt

                Common Internet Message Headers, Informational

  http://tools.ietf.org/rfc/rfc2822.txt

                Internet Message Format, Standard Track

  http://tools.ietf.org/rfc/rfc2821.txt

                Simple Mail Transfer Protocol, Standard Track

* Sending email via gmail in emacs.

; install starttls from here (no need for patch)

; http://josefsson.org/emacs-smtp-starttls.html

(setq send-mail-function 'smtpmail-send-it

   message-send-mail-function 'smtpmail-send-it

   smtpmail-starttls-credentials

   '(("smtp.gmail.com" 587 nil nil))

   smtpmail-auth-credentials

   (expand-file-name "~/.authinfo")

   smtpmail-default-smtp-server "smtp.gmail.com"

   smtpmail-smtp-server "smtp.gmail.com"

   smtpmail-smtp-service 587

   smtpmail-debug-info t

   starttls-extra-arguments nil

   smtpmail-warn-about-unknown-extensions t

   starttls-use-gnutls nil)

machine smtp.gmail.com login [your name]@gmail.com password [your password]

And finally download, unzip, make and install startttls:

http://josefsson.org/emacs-smtp-starttls.html

See

  http://justinsboringpage.blogspot.com/2009/02/sending-email-via-gmail-in-emacs.html

  http://obfuscatedcode.wordpress.com/2007/04/26/configuring-emacs-for-gmails-smtp

* Mail etiquette.

** Bottom vs. top quoting.

Just not use top quoting!

** Stallman warn about Google.

  http://www.mail-archive.com/gnu-emacs-sources@gnu.org/msg00302.html

* Storage format for email.

** mbox.

  http://tools.ietf.org/html/rfc4155

                The application/mbox Media Type (Category: Informational)

  http://en.wikipedia.org/wiki/Mbox

** maildir.

  http://en.wikipedia.org/wiki/Maildir

** MH mailbox format.

  http://en.wikipedia.org/wiki/MH_Message_Handling_System