See hier(7) for more of what is where & why.

E-mail used to live in /usr/spool/mail a long time ago. However,
the advent of diskless workstations and network filesystems made
some changes necessary, and other changes desireable, so a conference
of UNIX vendors was convened at Berkeley, and most of what you see
in NetBSD today was the result.

	Erik E. Fair	fair@clock.org