When you download and install Drupal, you are installing what is commonly called Drupal core. Core represents the “engine” that powers a Drupal-based website, along with a number of out-of-the-box features that enable the creation of a relatively full-featured website. The primary components of Drupal core include capabilities to create and manage
• file uploads/downloads
• user accounts
• roles and permissions
• discussion forums
• views to extract and display content in various forms such as lists and tables
• WYSIWYG-based content editor
Drupal core also includes a feature-rich search engine, multilingual capabilities, and logging and error reporting.
Although Drupal core can be used to build feature-rich websites, there are likely situations where core lacks the functionality needed to address specific requirements. In such cases, the first step is to search through the thousands of custom modules, contributed by developers from all around the world to the Drupal project, for a solution that meets your needs. It’s very likely that someone else has had the same functional requirement and has developed a solution to extend Drupal core to provide the functionality that you need.
To find a contributed module, visit the Drupal.org website at http://www.drupal.org/project/project_module. You will find a general list of categories and the current number of contributed modules (for all versions of Drupal) contained within each. Here is a short sampling of the types of categories and the number of modules you can find in each (modules are added to the list on a daily basis, and the number of modules in each category will have grown considerably since the time of this writing):
• Administration (1145)
• Community (614)
• Content (1981)
• Content Display (1612)
• Content Construction Kit (CCK) (673)
• Developer (960)
• E-commerce (892)
• Media (778)
• Third-party Integration (1908)
• Utility (1959)
To find modules that are supported on Drupal 8, select 8.x for the “Core compatibility” search filter. A few of the most popular contributed modules, and the ones that you will likely want to install, include the following (also check out the “Most installed” list to the right of the search filters):
Commerce: A full-featured web storefront module that provides all of the mechanisms required to sell products (physical as well as electronic downloads), collect credit card payments, and manage shipments. If you want to sell something on your website, this is the module you will want to use.
Display Suite: Allows you to take full control of how your content is displayed using a drag-and-drop interface.
Calendar: Provides the ability to create and render a list of events on a calendar.
Backup and Migrate: Handles scheduled backups of content in your Drupal database, with the ability to restore the database to a previous state based on one of the backup files created by this module. This is a must-have module for any production website.
Google Analytics: Provides a simple to use form for setting up Google Analytics on your site. Google Analytics is a free service that tracks the number of visitors to your website, where those visitors came from, what search terms they used to find your site, the pages they visited while on your site, how long they spent on your site, and many other useful metrics that will help you view and understand the usage of your website.