This page is currently under construction and might undergo drastic changes within a short span of time.

Categories are tags that index all pages marked with that tag on the same page. All pages marked with a particular category can be seen on one page. See Category: CEB for an example where all the pages tagged with the CEB category are then indexed on one page. This makes it easier for people to find content related to a topic or category.
Categorize pages using the official list of categories. Stick to these categories where possible; don't create new categories unless there is a real need.
Categorize pages by placing the Breadcrumb template at the top and passing the category name as parameter. At the top of a page about beekeeping, you would write {{Breadcrumb|Food and Agriculture|Beekeeping}}. This will do two things: insert a navigation menu at the top, and put the page in the appropriate wiki category.

Overview

Categories allow related pages to be grouped together easily.
For example, if you have pages A, B, C and D, you could link A to B, C and D, and link B to A, C and D, and link C to A, B and D, and link D to A, B and C... or you could link A to category X, B to category X, C to category X and D to category X. You've created 4 links instead of 12. Category X will automatically link to A, B, C and D.
The more related pages in a category, the better this works.

Categorizing a new page

First, see if there is an existing category for the page.
If so, create a link to the category at the bottom of the page. For example, this page is about using the wiki, so it belongs in the Wiki category:

[[Category:Wiki]]

If a category belongs in more than one category, create a link for each category.

If no existing category really fits, make up a new category and create the link:

[[Category:Cetaceans]]

Click on the category link and edit the category page.
- Describe what belongs in the category. Example:

Whales, dolphins and related mammals.

- If there's something similar that really belongs in a different but related category, point that out and link to the related category. Example:

Seals and walruses are listed under [[:Category:Pinnipeds|Pinnipeds]].

- If the category belongs to a larger category (for example, Cetaceans are aquatic mammals), create a link to the larger category:

[[Category:Aquatic mammals]]

To link to the Wiki category page, prepend a colon so that the parser sees a link (Category:Wiki) instead of a categorization:

[[:Category:Wiki]]

To change the appearance of a category link, append a vertical bar and the desired text to display (Style guide):

[[:Category:Wiki|Style guide]]