Drupal - Advanced Open Source CMS

Drupal is an open source content management system, which is famous for its flexibility, security and advanced core features. It is based on PHP and MySQL. Drupal lets you create a wide variety of websites ranging from simple personal websites to complex community websites. Most of the features are in its core, which is absolutely FREE, but the best thing about Drupal is that it has so many advanced modules and themes to extend its functionality and majority of them are free to use and download as well.

Because Drupal is an open source script, anyone can download, use, work on, and share it with others. It's built on principles like collaboration, globalism, and innovation. It's distributed under the terms of the GNU General Public License (GPL). So, there are no licensing fees, ever. Drupal will always be free. Drupal is supported by a large number of volunteers, professionals, web developers and support staff.

Major Features of Drupal:

1. Advanced content management system (custom content types and the flexibility to add a wide variety of fields in any content type)
2. Advanced user management system (custom user profiles, user roles with separate permissions and much more)
3. Availability of advanced e-commerce modules to create complex e-commerce websites
4. Advanced security and anti-spam features
5. Flexibility to combine features from different systems and modules (Rules, Token, etc.) to create complex workflows and systems
6. Availability for very powerful modules like "Views" & "Panels" to create complex displays and layouts via GUI
7. Built-in mobile responsiveness and optimization (Drupal 8 and 9)
8. Majority of contributed themes and modules are FREE to use.

Drupal Cons:

1. Somewhat complex to use for newbies
2. Too many versions available at the same time makes it difficult to choose an appropriate version for your project.

Drupal is the best choice for the following types of websites:

1. Websites involving advanced content sharing systems like news, magazines, info sharing websites, etc.
2. Websites involving advanced social and community features
3. Advanced e-commerce websites
4. Web Portals
5. Websites involving advanced workflows like project management systems, groups, CRMs, etc.
6. Websites with a lot of custom functionality, which is not available out-of-the-box anywhere in any CMS.

Drupal Versions:

There are two versions available for now.

1. Drupal 7 - This version is very much stable and most of the contributed modules and themes have stable versions for Drupal 7.
2. Drupal 8 and 9 - These two versions are almost identical and also stable but these are still missing the stable versions of many contributed modules and themes.