Drupal is a free- open source content management system (CMS) that is written in PHP and is distributed under General Public License (GNU).  For many different types of websites, personal blogs, large corporate and political sites drupal is used as back – end system.

Disadvantages:

• Though Drupal is considered to be a boon to the web world, it has some loopholes.
• The administration interface of Drupal is confusing, complex and especially daunting if you are using it for the first time.
• The new Drupal 7.0 may not be compatible with the older versions. Such a change will make the theme developers etc to reconstruct most of their codes in order to make it compatible with the newer version.
• Drupal is quite slow and time consuming especially when it is configured for narrow usage rather than the application designed for that usage. We also have to consider server resources while installing Drupal.

Advantages:

• It provides a high quality and standard platform for sites and it can work on all platforms.
• There is no need to install for multiple sites one time installation of Drupal would be suffice.
• All types of groups and user permissions are available in Drupal.
• It is useful in running not only CMS but community sites and membership sites also.
• It provides powerful templates for the sites.
• The code is of high quality and it is easy to integrate with other sources.
• Tremendous flexibility is available while working with Drupal.