1. Rapid website assembly - Build internal and external-facing websites in a matter of hours, with minimal custom programming. No need to start from scratch every time you build a new site.
2. Thousands of add-on modules - With more than 4 000 available modules, the vast majority of your site’s requirements can be addressed with Drupal core and available add-on modules. Focus your efforts on building great web sites, not re-creating well understood features available elsewhere.
3. Modular, extensible architecture - Drupal’s LAMP-based architecture is designed for extensibility - offering your developers and designers the freedom to address a wide range of site requirements. Create custom content types, views and user experiences to increase engagement across your web properties.
4. Social publishing infrastructure - Drupal provides a unified technical foundation for a broad range of collaboration patterns, including blogs, wikis, articles, forums, social networking, and much more.
Common user management and functional capabilities are available universally, simplifying training and adoption for people using the system.
5. Powerful UI customization options - Drupal’s presentation layer allows designers to create highly usable, interactive experiences that engage users and increase traffic. Drupal themes can range from simple to complex, support rich customization without requiring Dreamweaver or custom HTML and can be deployed to different sites on a mulit-site network.
6. Multi-site network management - Employ a single codebase for multiple web sites, enabling administrators to centrally maintain and upgrade code while serving similar or different content to different websites on different domains. Streamline site management while delivering a broad palate of social publishing capabilities to your users.
7. Thriving development community - With more than 900 contributors to the Drupal 6 release and 4 000 available modules, the Drupal developer community is very active and growing rapidly. This community drives the innovation that makes Drupal the preferred social publishing choice for web developers and site owners.
8. Zero software acquisition cost - Stop wasting valuable dollars on proprietary software licensing costs, which often results in unproductive, expensive audit and compliance programs to meet onerous licensing rules. Acquia’s Drupal distributions will be available to you at zero cost, saving money and freeing you to invest in value-added services that your unique deployment requires.
9. Industry standard LAMP stack - Drupal takes advantage of the scalable, secure and proven LAMP stack of open source technologies - GNU/Linux, Apache, MySQL, and PHP. Your web developers can access the source code across the stack, simplifying the development process and offering unrivaled flexibility, when compared to proprietary software.
10. Proven security track record - With a large, thriving developer community and thousands of sites with years of use, Drupal offers a mature, stable set of security capabilities for authentication, authorization, and protection against security threats. The Drupal community takes security seriously and marshals its vast resources against new threats in real time.
and one last thing to mention... Drupal is Fun!