(setq gnus-posting-styles
      '(("^comp.*" (signature choose-quote))
        ("-sig$" (signature choose-quote))
        ("cam.misc" (signature choose-quote))))

(defvar *quotes* '()
  "pearls for sigs.")

(defun setup-quotes (&optional file)
  "fill the list *quotes* from the file `file' where 
quotes are separated by blank lines.

`file' currently defaults to \"~/.comp.sig\""
  (interactive)
  (setf *quotes* ())
  (let ((buffer (create-file-buffer (or file "~/.comp.sig"))))
    (unwind-protect
        (save-excursion
          (set-buffer buffer)
          (insert-file-contents (or file "~/.comp.sig"))
          (let ((oldpoint (point-min)))
            (while (search-forward "\n\n" nil t)
              (setq *quotes* 
                    (nconc *quotes* 
                           (list (buffer-substring oldpoint (1- (point))))))
              (setq oldpoint (point)))
            (setq *quotes* 
                  (nconc *quotes* 
                         (list (buffer-substring (point) (point-max))))))))
    (kill-buffer buffer)))

(random t)

(defun choose-quote ()
  (nth (random (length *quotes*)) *quotes*))

(defun insert-quote ()
  (interactive)
  (insert (choose-quote)))

(defun insert-sig ()
  (interactive)
  (save-excursion 
    (goto-char (point-max))
    (insert "-- \n")
    (insert-quote)))

(defun replace-sig ()
  (interactive)
  (save-excursion
    (goto-char (point-max))
    (if (search-backward "-- \n" nil t)
        (delete-region (point) (point-max)))
    (insert-sig)))

(setup-quotes)