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(am-utils.info)Why Deliver Into the Home Directory?

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Why Deliver Into the Home Directory?
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   There are several major reasons why SAs might want to deliver mail
directly into the users' home directories:

Location
     Many mail readers need to move mail from the spool directory to the
     user's home directory.  It speeds up this operation if the two are
     on the same filesystem.  If for some reason the user's home
     directory is inaccessible, it isn't that useful to be able to read
     mail, since there is no place to move it to.  In some cases,
     trying to move mail to a non-existent or hung filesystem may
     result in mail loss.

Distribution
     Having all mail spool directories spread among the many more
     filesystems minimizes the chances that complete environments will
     grind to a halt when a single server is down.  It does increase
     the chance that there will be someone who is not able to read
     their mail when a machine is down, but that is usually preferred
     to having no one be able to read their mail because a centralized
     mail server is down.  The problem of losing some mail due to the
     (presumably) higher chances that a user's machine is down is
     minimized in HLFS.

Security
     Delivering mail to users' home directories has another advantage --
     enhanced security and privacy.  Since a shared system mail spool
     directory has to be world-readable and searchable, any user can see
     whether other users have mail, when they last received new mail,
     or when they last read their mail.  Programs such as `finger'
     display this information, which some consider an infringement of
     privacy.  While it is possible to disable this feature of `finger'
     so that remote users cannot see a mailbox file's status, this
     doesn't prevent local users from getting the information.
     Furthermore, there are more programs which make use of this
     information.  In shared environments, disabling such programs has
     to be done on a system-wide basis, but with mail delivered to
     users' home directories, users less concerned with privacy who do
     want to let others know when they last received or read mail can
     easily do so using file protection bits.

   In summary, delivering mail to home directories provides users the
functionality sought, and also avoids most of the problems just
discussed.