It has been a somewhat embarrassing secret. Until this weekend, pgedit.com was using MySQL for the content management system back end database. I intended to use PostgreSQL from the start, but the hosting provider only offered an old version (7.3) and there was a lack of necessary tools to run it properly. MySQL had an automatic installer that set everything up with a few mouse clicks.
Happily, pgedit.com is now running the latest version of Drupal and PostgreSQL 8. In addition to being a very nice content management system, Drupal provides a flexible framework for developing web database applications. There was a recent thread about this on the pgsql-general mailing list. Kevin Murphy pointed out the existence of some MySQL bias in the Drupal contributed modules and suggests the idea of a pool of Drupal/PostgreSQL testers to remedy the situation.