+@node Undo
+@section Undo
+@cindex undo
+
+It is very useful to be able to undo actions one has done. In normal
+Emacs buffers, it's easy enough---you just push the @code{undo} button.
+In Gnus buffers, however, it isn't that simple.
+
+The things Gnus displays in its buffer is of no value whatsoever to
+Gnus---it's all just data that is designed to look nice to the user.
+Killing a group in the group buffer with @kbd{C-k} makes the line
+disappear, but that's just a side-effect of the real action---the
+removal of the group in question from the internal Gnus structures.
+Undoing something like that can't be done by the normal Emacs
+@code{undo} function.
+
+Gnus tries to remedy this somewhat by keeping track of what the user
+does and coming up with actions that would reverse the actions the user
+takes. When the user then presses the @code{undo} key, Gnus will run
+the code to reverse the previous action, or the previous actions.
+However, not all actions are easily reversible, so Gnus currently offers
+a few key functions to be undoable. These include killing groups,
+yanking groups, and changing the list of read articles of groups.
+That's it, really. More functions may be added in the future, but each
+added function means an increase in data to be stored, so Gnus will
+never be totally undoable.
+
+@findex gnus-undo-mode
+@vindex gnus-use-undo
+@findex gnus-undo
+The undoability is provided by the @code{gnus-undo-mode} minor mode. It
+is used if @code{gnus-use-undo} is non-@code{nil}, which is the
+default. The @kbd{M-C-_} key performs the @code{gnus-undo} command
+command, which should feel kinda like the normal Emacs @code{undo}
+command.
+
+
+@node Moderation
+@section Moderation
+@cindex moderation
+
+If you are a moderator, you can use the @file{gnus-mdrtn.el} package.
+It is not included in the standard Gnus package. Write a mail to
+@samp{larsi@@ifi.uio.no} and state what group you moderate, and you'll
+get a copy.
+
+The moderation package is implemented as a minor mode for summary
+buffers. Put
+
+@lisp
+(add-hook 'gnus-summary-mode-hook 'gnus-moderate)
+@end lisp
+
+in your @file{.gnus.el} file.
+
+If you are the moderation of @samp{rec.zoofle}, this is how it's
+supposed to work:
+
+@enumerate
+@item
+You split your incoming mail by matching on
+@samp{Newsgroups:.*rec.zoofle}, which will put all the to-be-posted
+articles in some mail group---for instance, @samp{nnml:rec.zoofle}.
+
+@item
+You enter that group once in a while and post articles using the @kbd{e}
+(edit-and-post) or @kbd{s} (just send unedited) commands.
+
+@item
+If, while reading the @samp{rec.zoofle} newsgroup, you happen upon some
+articles that weren't approved by you, you can cancel them with the
+@kbd{c} command.
+@end enumerate
+
+To use moderation mode in these two groups, say:
+
+@lisp
+(setq gnus-moderated-list
+ "^nnml:rec.zoofle$\\|^rec.zoofle$")
+@end lisp
+
+
+@node XEmacs Enhancements
+@section XEmacs Enhancements
+@cindex XEmacs
+
+XEmacs is able to display pictures and stuff, so Gnus has taken
+advantage of that. Relevant variables include:
+
+@table @code
+@item gnus-xmas-glyph-directory
+@vindex gnus-xmas-glyph-directory
+This is where Gnus will look for pictures. Gnus will normally
+auto-detect this directory, but you may set it manually if you have an
+unusual directory structure.
+
+@item gnus-xmas-logo-color-alist
+@vindex gnus-xmas-logo-color-alist
+This is an alist where the key is a type symbol and the values are the
+foreground and background color of the splash page glyph.
+
+@item gnus-xmas-logo-color-style
+@vindex gnus-xmas-logo-color-style
+This is the key used to look up the color in the alist described above.
+Legal values include @code{flame}, @code{pine}, @code{moss},
+@code{irish}, @code{sky}, @code{tin}, @code{velvet}, @code{grape},
+@code{labia}, @code{berry}, @code{neutral}, and @code{september}.
+
+@item gnus-use-toolbar
+@vindex gnus-use-toolbar
+If @code{nil}, don't display toolbars. If non-@code{nil}, it should be
+one of @code{default-toolbar}, @code{top-toolbar}, @code{bottom-toolbar},
+@code{right-toolbar}, or @code{left-toolbar}.
+
+@item gnus-group-toolbar
+@vindex gnus-group-toolbar
+The toolbar in the group buffer.
+
+@item gnus-summary-toolbar
+@vindex gnus-summary-toolbar
+The toolbar in the summary buffer.
+
+@item gnus-summary-mail-toolbar
+@vindex gnus-summary-mail-toolbar
+The toolbar in the summary buffer of mail groups.
+
+@item gnus-xmas-modeline-glyph
+@vindex gnus-xmas-modeline-glyph
+A glyph displayed in all Gnus mode lines. It is a tiny gnu head by
+default.
+
+@end table
+
+
+@node Fuzzy Matching
+@section Fuzzy Matching
+@cindex fuzzy matching
+
+Gnus provides @dfn{fuzzy matching} of @code{Subject} lines when doing
+things like scoring, thread gathering and thread comparison.
+
+As opposed to regular expression matching, fuzzy matching is very fuzzy.
+It's so fuzzy that there's not even a definition of what @dfn{fuzziness}
+means, and the implementation has changed over time.
+
+Basically, it tries to remove all noise from lines before comparing.
+@samp{Re: }, parenthetical remarks, white space, and so on, are filtered
+out of the strings before comparing the results. This often leads to
+adequate results---even when faced with strings generated by text
+manglers masquerading as newsreaders.
+
+