Categories are internal links that, after being added to a page, provide automatic indexes that are useful as tables of contents. A category is a software feature of MediaWiki.
To add a page to a category type, for example:
For example, to add an article to the category "Law", you would edit the article and add [[Category:Law]] into the page source.
For the sake of regularity, by convention, the category is put at the end, after the article text.
Please use Categories that have already been established. To see already established Categories see the Contents Page. For a complete list of categories, see Special:Categories.
A category page does not need to be created before the creation of a page. Putting a category link in a page will automatically create that category and display the page (or pages) that belongs to it.
By looking at the very bottom of any page, you can tell what categories it contains, if any. Categories, if they exist, are always displayed there.
Although a category has multiple articles in it, it will appear as a red link when a description of the category page is empty.
To make the category links appear blue (like existing articles), click on the category link to go to the category page and edit it to add a short description.
When creating new categories, follow the established conventions.
For example, to create a category for a person, use this format Category:Last Name, First Name (yyyy-yyyy).
After creating a category page for a person add to that page to have it appear in the complete People category Index.
For United States and other nation's cities follow the format Category:State name-City. Then add the Category:State name to the resulting page.
For a category to work it must include the exact format, punctuation, and spacing. (When in doubt cut and paste).
Categories have sub-categories, meaning that you can put a category page inside of another category. Categories can be nested in multiple level in this fashion. For example the "Social Sciences" category may contain a list of categories such as "Sociology", "History", etc. That is how the People category is set up, each category for an individual is sub categoried under People. It also allows so categories to be into several hierarchies for example the Category:Sodomy Law can go under both Category:Sodomy and Category:Law. For questions about how this functions, we suggest you look at how existing Categories have been set up.
Linking to a Category Page
To link to a category page (without adding the page to the category), include a colon before the complete Category page name. For example, [[:Category:People]] renders as Category:People.
Singular or plural
It is not obvious whether a page like Amsterdam should be in category City (a description of a member of the category) or Cities (a description of the category as a set of pages). A convention for using one or the other is useful and should be codified. (Here is Wikipedia's convention). Sticking to the convention will help to avoid having both categories, with part of the pages in one, and part in the other.
Moving a category page
The only way to move a category page is to manually change all category tags that link to the category, and copy the editable part. There is no automatic way to move a category page in the way one moves an article page.