A custom namespace is a new namespace, created additionally to the standard 18 namespaces and 2 special namespaces that exist in every wiki.
There is currently no way of creating new namespaces via the wiki interface installed, so this needs to be done by someone with server access. Because of the maintenance time involved in doing this, each wiki is only allowed three custom namespaces (plus the three associated talk namespaces), and they must follow the rules below.
What restrictions are there on namespace creation?
There must be consensus on your wiki for the addition of the namespace.
The namespace must not be the same as any of the names in the interwiki map.
There must not be any pages in the custom namespace before it is created -- this means you can't have any pages (including redirects) with a title of the form "Custom namespace name:Pagetitle". Any such pages will be inaccessible after the namespace addition.
Every namespace will have a talk namespace associated with it. This will usually be at "Custom namespace name_talk:" unless you request otherwise.
How do I request a custom namespace?
If you want to request more than one custom namespace (you can ask for a maximum of three), please request them all at once rather than on three separate occasions. Please decide these choices for each namespace, and include it in your initial request to speed up the process and processing.
Should the new namespace be considered "content" or not?
That is, are the pages about the topic of the wiki, not about wiki administration, news, opinions, or other things that your community doesn't count as "real" pages.
Content namespaces are included in article counts and maintenance lists
Content namespaces are included in results for Special:Random
A good example of a content namespace would be the Comics: namespace on the DC and Marvel wikis, those are content.
Should the new namespace be visible in search results by default?
Unless you have an unusual wiki setup, this answer would usually be "yes" for a content namespace.
Users can still search the namespace using the checkboxes, this choice is only about if the checkbox is defaultly checked.
Should the new namespace have subpages?
By default, we enable subpages for all new namespaces unless told not to. Please inform us if you have unique/specific intentions for the namespace.
What should the talk namespace be called?
If you request "Foo", the talk pages will be "Foo_talk"
This is often important in other languages.
Make your request using the Special:Contact form. To help us respond quickly, be sure to include the answers to the above questions.
Some Common Custom Namespaces
While custom namespaces can be used to organize anything, there are some common namespaces communities often request. While you are not limited to these, we want to illustrate some typical uses:
Portal: A typical gaming namespace that functions as a point of access to similar information on the wiki.
Episode: Entertainment wikis focusing on television shows often like to put all of their articles about series episodes into the same namespace.
News: Wikis that want to publish official press releases about their topic from game creators, movie studios, etc., etc.,
Gallery: For pages meant to solely house an image gallery about a wiki topic.
Help:Namespace - for general information about what namespaces are and a list of the default namespaces wikis have.
Help:Special pages - a guide about how some Special Pages can help you view and organize namespace pages.