Intersection Analysis Search Tool

How do I use this?
The three circles on the left represent three 'sets' of search results. To fill each circle with results, enter a search term in the light-blue text-box next to the circle, and click on 'go' Numbers will then appear in the circles, showing the number of resources that match each search box. The intersecting areas between the circles show the number of resources that match the two adjacent searches (or three in the case of the central region). To see the resources that match each region, click on the numbers, and the resources will be listed below as live links.