What a fantastic plugin, thank you for coding it up! I've got 4 custom taxonomies imported (using CSV Importer) and I'm able to display posts that have a matching taxonomy, e.g. http://sample.com/column/featured/
I looked at my Simple Taxonomies setup page, and made sure the setting for:
Disable the "post_tag" taxonomy?
is unchecked. Hmm... apparently something is not working right -- deactivated the plugin, and the category or tag URLs still don't work. Something else is not good in WordPressVille. :(