Drupal’s taxonomy system is an extremely powerful tool for organizing the content on a website and, combined with the features of the Pathauto module, is the basis for creating the overall silo website architecture. Taxonomy, another name for categories, are defined in groups of vocabularies and can be assigned to any or all content types. When creating content, you have the options to enable hierarchical tagging, multiple keyword tagging, or free tagging.

The categories you create in your vocabularies should reflect the main targeted keywords for the overall theme for your website optimization. Taxonomy is included in Drupal’s core and is enabled by default.

To set up your categories, navigate to Administer > Content Management > Categories > Add Vocabulary.

Because of how we have configured the Pathauto module, what you name your Vocabulary is of little importance because it will not appear in the URL structure. It can be as generic as “Category”. Select the content types that should be attached to the vocabulary.

Under Hierarchy, you have the options to select Disabled, Single, and Multiple. What you choose here depends on the needs for your site and what you are trying to accomplish. Selecting Disabled will mean that your categories will remain on the same level and will not have any parent-child relationships or subcategories attached to them. “Single” will give you the option to create subcategories with your terms and enable a parent-child relationship. With Single, a child term can have only one parent. The “Multiple” option enables a child term to have multiple parents. I usually always select “Single” and make adjustments later if needed.

The remainder of the selections, (Related terms, free tagging, multiple select, and required) are optional.

When choosing the “multiple select” option, you will be able to place your content into multiple categories. However, the pathauto module will only place one term into the URL alias, and this is controlled by weight, with the lightest term pulled first into the url. Additionally, you can attach multiple vocabularies to each content type and the term from the lightest vocabulary will appear in the URL alias.

When you go to create a new page, you will see an additional drop down menu titled whatever you named your vocabulary. Here you select the term you want associated with your page, placing it into the “directory” on your server. The pathauto module will take this term and place it into the url linking structure.
Furthermore, all nodes associated with the term you choose will be accessible from the url http://www.example.com/your-term/ . Depending on the Theme you choose for the basis of your site, the taxonomy terms will appear as links on each post and in the breadcrumb.