Lists (post) categories used on your blog in a table with links to subscribe to topic feeds using popular on-line feed readers.
You add a shortcode to your page or post and the plugin will render it as a table of your feeds with buttons for RSS, Google, Bloglines, and Yahoo. You can configure the listing to a certain extent.
At present the listing is ordered alphabetically by the category URL. Provided your feed URL's follow the usual pattern, this ordering will also reflect the hierarchical structure of your categores. Sub-categories will be indented below their parent.