Four major groups of templates
Channel - A Channel template will generally be implemented as a unit's landing page.
Category - Category templates are designed to surface multiple pieces of content contained deeper within the site's architecture. They are to be used one level below channel pages, and are landing pages to wide subjects, topics, or areas. They have a larger page title and often contain graphic elements that represent a collective visual, displaying a summary of the content enclosed in the pages below. The main difference between category and content pages is their purpose and layout. Category pages are designed for quick scanning and reading. They are supposed to direct the user to a deeper content level–content pages.
Content - Content templates are are intended for use in the overall site architecture, and are designed to house specific content about a topic. These templates are generally less visually complex and used mostly for text-based content.
Unique - Unique templates are used for specific types of content, for example, University policies, press releases, profile pages.