This plugin will create widgets that you can use to conduct faceted searches using the categories or tags on your site.
A good example of a faceted search is the directory newegg.com uses. Basically, you can select a couple categories (or tags if your using the tag widget), do the search, and the search will yield only articles that belong to all the selected categories (or selected tags). It's a good way to narrow down searches.
They both work pretty much the same, except that one goes by the categories on your site, and the other goes by the tags on your site. Just check the checkboxes next to the categories (or tags) that are relevant to your search, and click 'search'. The real challenge becomes organizing your articles into categories that will allow for intuitive faceted searching, and I can't help you with that.
Once the plugin's installed, just edit the faceted-search.css file that's in the faceted-search folder to style the lists of categories and tags. If you want different images for the bullets, just replace the ones already in this plugin's image folder with whatever you want.
A common solution to this problem is deactivating and reactivating the plugin.
As of version 3.3, there are textboxes in the widget options where you can enter a comma-separated list of tags or categories to exclude from, or disable within, your widget.
Select the "Get" request method in your widget. Please note that since this will display the search query in the URL, if you are displaying many categories in your category tree this may become too many characters for your browser's address bar. Use at your own discretion. From what I've read, while http standards say there is no limit, popular browsers might have a URL character limit of around 2000.
To get paged results, you need to switch it to use the "Get" request method.