Can I use display-filters on the message index?
No. But there is a work-around. In (M)ain (S)etup (C)onfig, make sure that the following options are set:
[X] print-offers-custom-cmd-prompt [X] print-index-enabled
Then, in the message-index, (%)Print (I)ndex (C)ustomCmd and type in the name of your filter command.
For a reason why this would be useful, see this thread.
I have a text file full of email addresses. How do I make a Pine distribution list out of it?
(C)ompose a new message. Leave the To: and other recipient fields blank. (^R)ead the file into the message body, then ^X to send the message. It will only get copied into your sent-mail folder.
Go to your sent-mail folder, and open that message. Then, (T)ake to (A)ddressbook and (L)ist mode, then Set(A)ll.
You may also choose to be more selective and exclude some or select addresses manually, rather than selecting them all.
How do I change the content-type when composing new mail?
Eduardo Chappa posted instructions to comp.mail.pine. Please read his message in the archives.
Can I change the naming convention for the Fcc folder?
Eduardo Chappa suggested an interesting idea with environment variables to put mail from each month into its own folder. You can read that thread in the archives. His idea can be extended to other nifty purposes.
How can I get self-signed certificates to work with Pine?
Make sure that the certificates are in the correct location on the server. For OpenSSL on Unix, this is usually in /usr/local/ssl/certs, so that Pine can correctly validate the certificate. If that doesn't help you can check out some more detailed pages: Paul Heinlein's Pine+OpenSSL HowTo or Nick Burch's Certificate Management with OpenSSL.