You'll need to know basic CSS and HTML and know how to look up forums to solve issues. Easy to use for developers and newbies. You can build a site without any html knowledge.
You'll need to know advance CSS, PHP and HTML and know how to look up forums to solve issues. Community centered forum, with strong social networking component.
You'll need to know advance CSS, PHP primarily. Forum look up and cross platform (other CMS) referencing needed to solve issues. Powerful frame work, easily tag and organize complex structured content.
You'll need a proficient PHP developer and dedicated designer to develop your store.
What they say!
It's the most used CMS in the world to create websites & blogs.
Build powerful, scalable, secured websites. Meant to be managed by groups for large scaled sites!
Supported by a strong developer community Drupal is trusted by millions of websites.