From ConspiracyWiki

A category is a software feature of MediaWiki. Categories provide automatic indexes, that are useful as table of contents. Together with links and templates they structure a project.

Putting an item in a category

A page in any namespace can be put in a category by adding a category tag to the page (by convention, at the end of the page), e.g.:

[[Category:Category name]]

This lists the page on the appropriate category page automatically and also provides a link at the bottom of the page to the category page, which is in the namespace "Category". Pages can be included in more than one category by adding multiple category tags. These links do not appear at the location where you inserted the tag, but at the page margin in a fixed place, depending on the skin (the bottom for Monobook, the upper right corner for Standard). Category tags may be placed anywhere in the article, although they are typically added to the end of the article to avoid undesirable text display side effects. Category links are displayed in the order they occur in the article, unlike the automatic ordering of lists in the category pages themselves (see below).

Executive summary

Each of the pages in the Category namespace represents a so-called category, a kind of grouping of related pages. For example, this pa