[dabean]

Those classes all work by quering dmoz then reparsing the html returned before displaying it. The advantage is you get "live" data.

However the disadvantage is that using a fetch > reparse system to completely remove all the formating nessasary to use the raw data inside a vb template is extremely complex and would place a high load on your server. However parsing off the header and footer is relatively simple as long as you leave the copyright credit alone which those classes do.

A simpler method is the use the RDF dumps which weigh in at a few hundred mb's with a cron job to periodically refresh them.
The advantage of using the RDF dump is it is possible to parse the data using the xml module provided with php and that the data contains no formating elements so complete stylistic control is possible.

For example yahoo and google use the later method so they can reformat the data to suit their requirements.
Whilst it is more common for sites that do not wish to completely alter the layout to choose the first method.