When you press those magical C-c C-c keys to ship off your latest (extremely intelligent, of course) article, where does it go?
Thank you for asking. I hate you.
It can be quite complicated.
When posting news, Message usually invokes message-send-news
(see News Variables in Message Manual).
Normally, Gnus will post using the same select method as you’re
reading from (which might be convenient if you’re reading lots of
groups from different private servers). However. If the server
you’re reading from doesn’t allow posting, just reading, you probably
want to use some other server to post your (extremely intelligent and
fabulously interesting) articles. You can then set the
gnus-post-method to some other method:
(setq gnus-post-method '(nnspool ""))
Now, if you’ve done this, and then this server rejects your article, or this server is down, what do you do then? To override this variable you can use a non-zero prefix to the C-c C-c command to force using the “current” server, to get back the default behavior, for posting.
If you give a zero prefix (i.e., C-u 0 C-c C-c) to that command, Gnus will prompt you for what method to use for posting.
You can also set gnus-post-method to a list of select methods.
If that’s the case, Gnus will always prompt you for what method to use
for posting.
Finally, if you want to always post using the native select method,
you can set this variable to native.
When sending mail, Message invokes the function specified by the
variable message-send-mail-function. Gnus tries to set it to a
value suitable for your system.
See Mail Variables in Message manual, for more
information.