Pearl Harbor sucked.
A good taxonomy system would:
- Enable you to define an unlimited number of levels for containers.
- Enable you to label each level.
- Enable you to place each object in more than one container.
- Enable you to place each container in more than one container.
Joomla has three levels, no more and no less. Their labels are hard coded. Each object and each container must belong to a container and can only belong to one container. It's exactly what you would design if you had never seen software before.
Wordpress used to be slightly worse, but I believe that it was fixed some time ago to allow an unlimited number of nested categories. That makes Wordpress's taxonomy system better than Joomla's.
NetBuilder Tearabite has a fairly nice Drupal setup at GrownUpGeek.