Sometimes the relevance of a technology only becomes apparent after examining it's origins.  For the uninitiated, I'll drop back a few sentences here to help understand Drupal's roots, before talking about some of the interesting things people are doing with it. 

Drupal was created by Dries Buytaert in 2001.  Drupal is licensed under the GPL and is written in  PHP.  It is typically deployed in a LAMP environment although a few prominent sites have deployed Drupal on Solaris.  Drupal 5 is the current release with Drupal 6 due out in fall of 2007.The popularity of Drupal has been driven by a passionate group of developers who come from very diverse backgrounds and who have applied Drupal to an equally diverse range of needs. 

The early community of Drupal developers grew primarily through rapid adoption by Web 2.0 hobbyists, nonprofits, and political activist organizations.  Howard Dean's push for the U.S. Presidency in 2004, noted for leveraging online tools and communities, owes much of its success to the Drupal powered 'Deanspace'.  This highly visible use of Drupal drew much attention to the community and triggered a huge wave of Drupal adoption. 

One of the most interesting uses of Drupal that I've seen is that which was presented at DrupalCon by Ivan Labra from SPAWAR, the Space and Naval Warfare division of the U.S. DoD.  He is using it as a integration platform in support of SPAWAR's peace and stabilization efforts, in which basic integrated ICT capability must be deployed into austere and sometime unstable environments.  Known as Speed-to-Capability, this project defines a technical architecture and deployment strategy for quickly building communication and collaboration capacity FOSS components combining PBX (Asterisk), Instant Messaging/Chat (Jabber), email (Postfix) and software provisioning (HostMaster) capabilities on the Drupal framework.   In my role advising on technology capacity in the developing world, I hope to work with Ivan in the future to apply this important communication and collaboration capacity.