AbbrevMode works in Gnus.
From that link (with some edits):
Defining Abbrevs
Type the word you want to use as
expansion, and then type ‘C-x a g’ and
the abbreviation for it. Example:
This is the text of an opening paragraph.Esc h Ctrl-u 0 Ctrl-x a gopenReturn
Me: That's a zero after the C-u. Together they make the abbrev definition C-x a g apply to the selected region, which is a paragraph, in this case, which the M-h (Esc-h or Alt-h) selected. The abbrev definition can be made to apply only to the current major mode instead of globally by using C-x a l (that's an "ell" instead of the "g").
Saving Abbrevs
Use ‘M-x write-abbrev-file’ and just
hit RET when asked for a filename. The
default is “~/.abbrev_defs”. In the
future, Emacs should save the abbrevs
automatically when you quit Emacs.
Also, if you want abbreviations to be
saved whenever you save files (C-x s)
or quit emacs, add the following to
your .emacs:
(setq save-abbrevs t)
Restoring Abbrevs
Use ‘M-x read-abbrev-file’ to read the
abbrevs, or better yet, add the
following to your ~/.emacs file:
(quietly-read-abbrev-file)
This will read the definitions
from the default file,
“~/.abbrev_defs”.
Using Abbrevs
‘M-x abbrev-mode’ toggles Abbrev mode.
You can also put the following in your
~/.emacs file if you want it always
on:
(abbrev-mode 1) Actually, you may have to do:
(setq default-abbrev-mode t) I’m not really sure why.
me again: Once abbrev-mode is on, typing an abbreviation followed by white space causes it to be immediately expanded. However, if you don't want that to happen you can leave it turned off and expand them manually like this:
openCtrl-x a e
becomes:
This is the text of an opening paragraph.