The following are general guidelines for what should and should not go in the wiki. See MeatBall:AppropriateMedia for the theory behind these choices.  

Appropriate for the wiki: 
* Documentation which is not part of the official Emacs manual. 
* Examples, typical usage, customizations, and code snippets. 
* If you notice that a particular piece of code on Emacswiki does not work you may indicate this on the wiki page along with the version of Emacs you are using. 
* Questions about the stuff posted on the wiki can remain in the wiki until they have been given satisfactory answers.  
* Cross-posts from other media and discussions, [[CrossPosting with caveats]].

Inappropriate for the wiki: 
* Bugs in Emacs should be reported using ##report-emacs-bug##.  
* Bugs in the Emacs manuals should be reported to the
maintainers.
* Bugs in packages should be reported to the
appropriate maintainers.
* Discussions, questions, etc. usually go to the following places: 
** [http://savannah.gnu.org/mail/?group_id=40 Emacs mailing lists]
** [http://emacs.stackexchange.com/ Emacs Stackexchange]
** [http://www.reddit.com/r/emacs Reddit]
** EmacsNewsgroups


I hope that doesn't discourage people from adding new content.  The most constructive wiki citizen is a bold editor.