zlocaldepth is a plugin that properly handles the idea of a depth variable
when used with the config plugin. Blosxom’s built-in depth variable can only
be set from the cgi script. If set from a config file, it has to be calculated
relative to the absolute url, which can vary if you work on different machines.
In short, it is too unreliable to use flexibly.
Enter zlocaldepth. It allows you to set a depth for each directory of your site, when used in combination with the config plugin. For instance, your home page might only show articles in datadir. But you want your datadir/humor page to show all of the latest jokes in your various subcategories. This can all be done simply by placing the appropriate config files throughout your site.
PS> The name starts with a z so that the plugin loads after all (well, in theory) plugins that affect the filter subroutine have done their work.