[Dovecot] IMAP instead of Maildir on Ubuntu Precise

[Thufir]

Why is dovecot using Maildir and not IMAP.  Or is it using even using 
Maildir at all?

Currently I'm using mailman, postfix and dovecot to manage a mailing 
list.  Mail is sent to thufir at dur.bounceme.net which the "mail server 
delivery agent stack provided by Ubuntu server team" of dovecot-postfix 
handles fine, keeping it locally, so far as it goes.  The mail ends up 
in /home/thufir/Maildir, which the balsa mail client reads fine, as it 
handles Maildir fine.

However, I would like to use dovecot-imapd which is installed.  However, 
it's not clear quite how to switch over to IMAP.  I see:

root at dur:~#
root at dur:~# nl /usr/share/dovecot/protocols.d/imapd.protocol
      1	protocols = $protocols imap
root at dur:~#
root at dur:~# grep protocol /etc/dovecot/dovecot.conf
# Enable installed
protocols !include_try /usr/share/dovecot/protocols.d/*.protocol
root at dur:~#

which indicates to me that IMAP is configured.  So, why is mail showing 
up using Maildir?

I'm looking at:

"Once you have chosen, amend the following line in the file 
/etc/dovecot/dovecot.conf:

protocols = pop3 pop3s imap imaps"

https://help.ubuntu.com/community/Dovecot


Admittedly, I've not looked too closely into Dovecot man pages as I 
don't want to get too deep into the weeds on that if it's not even 
Dovecot I need to configure.  I'm assuming that it's dovecot which is 
using Maildir:

root at dur:/etc/postfix#
root at dur:/etc/postfix# grep dovecot main.cf
smtpd_sasl_type = dovecot
smtpd_sasl_path = private/dovecot-auth
mailbox_command = /usr/lib/dovecot/deliver -c 
/etc/dovecot/conf.d/01-mail-stack-delivery.conf -m "${EXTENSION}"
root at dur:/etc/postfix#


Can I force dovecot to only ever use IMAP and never use anything else? 
Is it maybe postfix which is using Maildir, and this is why my mail 
shows up as Maildir type mail?


thanks,

Thufir








thufir at dur:~$
thufir at dur:~$ head .balsa/config -n 20

[mailbox-Inbox]
Path=/var/mail/thufir
Type=LibBalsaMailboxMbox
Name=Inbox

[mailbox-Outbox]
Path=/home/thufir/Maildir/outbox
Type=LibBalsaMailboxMbox
Name=Outbox

[mailbox-Sentbox]
Path=/home/thufir/Maildir/sentbox
Type=LibBalsaMailboxMbox
Name=Sentbox

[mailbox-Draftbox]
Path=/home/thufir/Maildir/draftbox
Type=LibBalsaMailboxMbox
Name=Draftbox
thufir at dur:~$