This website is implemented using Drupal 5, an extremly powerful software package "that allows an individual or a community of users to easily publish, manage and organize a wide variety of content on a website". It's great for blogs and personal websites, collaborative authoring, newsletters and podcasts, as well as acting as a framework for more complex interactions. There are literally hundreds of contributed modules for Drupal that do everything from putting Google Maps onto your pages, implementing a complete commerce/shopping cart site, WYSIWYG editors, and content suggestions engines.
The actual software is Open Source (under GPL license), so we can modify and extend it as required. It is implemented in PHP and MySQL, so it's easy to deploy and maintain, and quick to get up and running. Development costs are very reasonable, and Drupal community activity is exploding right now! We are using Drupal as a basis for a couple of different projects that we're implementing right now. More news as it comes to hand!