Each mail message is stored in a folder. A Pine folder is
    equivalent to a VMS MAIL folder in a VMS MAIL mail file.

    While both Pine and VMS MAIL folder names are case sensitive,
    Pine users must be much more mindful of this fact. (VMS MAIL
    automatically converts folder names to upper case unless you
    surround the folder name with quotes.)

    For VMS MAIL files, a new folder is automatically created the
    first time a message is saved to it; a folder is automatically
    deleted when all messages in the folder are deleted. So when you
    use the Create folder command in Pine to create a new folder, the
    folder will be created with a placeholder message in it.