qmail lets each user control all addresses of the form user-anything.
Addresses that don't start with a username are controlled by a special
user, alias. Delivery instructions for foo go into ~alias/.qmailfoo;
delivery instructions for user-foo go into ~user/.qmail-foo. See
qmail-upgrade.0 and qmail-alias.0 for the full story.

Here's a checklist of aliases you should set up right now.

* Postmaster. You're not an Internet citizen if this address doesn't
work. Simply touch (and chmod 644) ~alias/.qmailpostmaster; any mail
for Postmaster will be delivered to ~alias/Mailbox.

* MAILER-DAEMON. Not required, but users sometimes respond to bounce
messages. Touch (and chmod 644) ~alias/.qmailmailer-daemon.

* Anything in /etc/aliases. You may have some aliases in /etc/aliases
that you want to keep. .qmail files are similar to .forward files, but
beware that they are strictly line-oriented---see qmail-alias.0 for
details. You'll probably want to transfer mailing lists to user control
as soon as possible, but you'll have to set up some centralized
forwarding unless your mailing list addresses are already of the form
user-whatever.

* root and other non-user accounts. qmail defines a user as a non-root
account that owns ~account. Non-user accounts don't get mail. Your
system may generate mail messages to root every night; if you don't have
an alias for root, those messages will bounce. (They'll end up
double-bouncing to the postmaster.) Set up an alias for root and for any
other non-user accounts that normally receive mail.

Note that special users such as ftp, www, and uucp should always have
home directories owned by root.

* Default. If you want, you can touch ~alias/.qmail-default to catch
everything else. Beware: this will also catch typos and other addresses
that should probably be bounced instead. It won't catch addresses that
start with a user name---the user can set up his own ~/.qmail-default.
