1) CMS: Content Management System - Manage content yourself and eliminate a majority of web admin fees - You have the ability to assign user roles. Give different departments control over the content that pertains to them, give an Intern or Employee the ability to update and add content in certain areas on your website or just have one Web Admin that can do it all. It’s your choice!
2) Open Source: This means it’s FREE with no license fees! It also means that people are always working to create new modules and improve existing ones. If something isn’t possible in Drupal now, nine times out of ten someone is working on making it possible right now!
3) Accepted Widely: White House, Nike, eBay, and Twitter. These are just some examples of Government and Corporations using Drupal that the majority of people will recognize.
4) SEO Friendly: Drupal comes configured to be SEO friendly and since it is modular, there are already modules in place you can install to make it even more SEO friendly. Some of nifty built in features include clean URL’s and automatically generating page titles based on content.
5) It's Modular: Not to be confused with tubular, though it is pretty awesome. There are a lot of modules available so development costs are significantly lower. Specific features can be custom programmed but for most part modules (pre coded software) is available such as shopping cart, blog or events calendar.
Please visit http://www.greenbirdmedia.com/client-resources/videos for informational videos on Drupal.