"The two primary formats for mail storage in Linux and Unix are
Mbox and MailDir. There are several other formats out there as
well, including MMDF (a close cousin to Mbox), MH (similar to
MailDir, but used more in IMAP mail senarios), and BABYL. Other
than Mbox and MailDir, most other formats are either deprecated,
obsolete, or in very limited use. Hence most end users won't
encounter said formats and thus don't need to worry about them.
Therefore, we'll only concentrate today on the primary two
"To get started, we'll look at the Mbox format. Mbox is one of
those old Unix standards that refuses to die, and for good reasons,
as I for one feel it's the better format. And it's not some rusty
old relic of days gone by, it's still a format that's in constant
development. I believe the current version is 7.0 which
incorporates even more new mail features available on the web, as
well as improved support for a variety of security systems."