Drupal started out in 2001 as a forum content management system (CMS), but has evolved into a strong middle-of-the-road content management framework (CMF). Drupal Core and Drupal.org contribited modules are all GPL v2. Its framework benefits from a well-balanced module, development ecosystem. There are a variety of basic levels of abstraction, with fields, entities, bundles for content, and hooks pretty much all the way down that other modules and themes can work with. Bunches of module state+configuration can be saved as a Feature, and make files and install profiles are used to form Distributions for building and provisioning new sites.
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- Drupal CMS Benefits - "Drupal is a publishing platform created by our vibrant community and bursting with potential. Use as-is or snap in any of thousands of free designs and plug-ins for rapid site assembly. Developers love our well-documented APIs. Designers love our flexibility. Site administrators love our limitless scalability. Drupal's content management features make it easy to create and manage your site."
- Introduction to Site Building with Drupal 7 - Lullabot.Drupalize.me
- Summary of Site Building with Drupal - Lullabot (Drupal 6)
Site building skills
- Skill set
- The Drupal Learning Curve: a configurators view - A good overview of techniques and modules Drupal users will most likely learn over time.
News and blogs
- http://drupal.org/project/issues/user - link to bookmark for viewing drupal.org issues you are participating in and have subscribed to
- New template system - July 28, 2004
See also D8
- Drupal 8 issues
- HTML5 in core
- Drupal.org should collect stats on enabled sub-modules and core modules - January 23, 2011
- Upgrade path for blog module removal - August 29, 2011
- -meta- Unofficial Drupal 8 Framework initiative - July 20, 2011
- Adopt PSR-0 namespace convention for core framework classes - August 5, 2011
- -meta- Make core maintainable - August 21, 2011 
- Establish heuristics for core feature evaluation - September 8, 2011
- Namespace strategy for module-provided classes - September 26, 2011
- Add a CSS preprocessor to core - October 15, 2011
- Convert DBTNG to namespaces; separate Drupal bits - October 25, 2011
- Consider composer.json as a replacement for .info files - January 9, 2012
- Change notification: Proposal for unified namespace organization - January 11, 2012
- PHP project structure survey - January 14 2012
- Introduce Composer for Symfony component management - February 1, 2012