July, 2007: Tried to turn off or minimize email notification. In config editor, changed "alerts.totalOpenTime" from 4000 (msec) to 1. Didn't seem to help. Found a web page that said you're supposed to be able to turn off mail notification by setting update.showSlidingNotification mail.server.default.notify.on to false, but that it's broken in Thunderbird 1.5. For a workaround, see http://kb.mozillazine.org/Disable_the_new_mail_system_tray_icon
July 21, 2004: Useful trick is to copy an email to a local folder to be able to edit it (to correct dates, add subject lines, remove unnecessary huge attachments). But when copying it back to an IMAP folder, would sometimes get error messages about a bad header (if I remember the wording of the error message correctly). Found it was due to a ">" added by Mozilla mail at the beginning of a "From" line in the header of the message, which can be easily fixed with an editor.
It contains info helpful for converting emacs email files to Netscape format, for recovering accidentally deleted emails, or for dealing with occasional malformed email messages or bugs in Netscape. A search at Google.com would probably uncover a more complete list of the Mozilla-status codes somewhere...
Note: one gotcha is that Netscape files emails by the date the sender
claimed to send it. If the sender has a Y2K problem or otherwise an
incorrect date (like the year 101 instead of 2001), then the email might
get filed at the end of your folder instead of where you expected it, and
so might appear to have "disappeared". This isn't Netscape's fault, but
just something you need to watch for occasionally.