IMAP diagnostics questions

[jesse@phiwumbda.org (Jesse F. Hughes)]

Hey ho.

In the Group buffer, when I hit "g", nnimap opens each group like so:

(From the lossage buffer, so upside down)

Opening nnimap server on PW+nnimap+PW:INBOX.kun...done
imap: Plaintext authentication...
Waiting for response from phiwumbda.org...done
imap: Opening SSL connection with `openssl s_client -quiet -ssl3 -connect %s:%p'...done
imap: Opening SSL connection with `openssl s_client -quiet -ssl3 -connect %s:%p'...
imap: Connecting to phiwumbda.org...
Opening nnimap server on PW+nnimap+PW:INBOX.kun...

Well, my first question: Is that plaintext authentication *really*
plaintext or not?  If I'm doing this over the internet, can my
password be sniffed?

Second, is it necessary to establish the connection *every* time I get
new mail?  I like to use gnus splitting with ifile, so it's not
sufficient just to check INBOX (though I have set some levels so that
some groups are only occasionally checked).  If I use a daemon to do
this when idle, then it will thwart tkbiff, which reads only INBOX.  I
don't want to run BIGNUM copies of tkbiff.

Is there a way to keep existing connections alive for a period of
time?  

Also, in my server buffer, in addition to 

     {nnimap:PW} (opened)

I also see a slew of lines like

     {nnimap:PW+nnimap+PW:INBOX.lists.categories} (opened)
     {nnimap:PW+nnimap+PW:INBOX.tue} (opened)
     {nnimap:PW+nnimap+PW:INBOX.tue.research} (opened)
     {nnimap:PW+nnimap+PW:INBOX.trash.manual} (opened)

Is that normal?  If I enter one of those "servers", I see a list of
all the existing IMAP groups marked "K".

Thanks for any help you can offer this small-brained person.
Remember, talk slow and use non-technical words.  Dammit, Jim, I'm a
philosopher, not a programmer.

-- 
Jesse Hughes
"She testified they had sex near the Oval Office, not in the famous
room itself, because that `wouldn't be appropriate, you know.'"
                                         -AP article