Question 5.2

How to enable automatic word-wrap when composing messages?

Answer

Starting from No Gnus, automatic word-wrap is already enabled by default, see the variable message-fill-column.

For other versions of Gnus, say

(unless (boundp 'message-fill-column)
  (add-hook 'message-mode-hook
            (lambda ()
              (setq fill-column 72)
              (turn-on-auto-fill))))

in ~/.gnus.el.

You can reformat a paragraph by hitting M-q (as usual).