This dashlets takes the Site name as input, and performs a Google search, limiting the search to what has been indexed the last 5 days. Search terms and number of days are configurable. It does NOT show an index of your internal content.
The use case is a Marketing manager creating a product launch site. To able to monitor what is said about your company or your product, the marketing manager ads a dashlet that lists all that has recently been indexed by Google. This is why the dashlet was named Google Site News, but your usage may very well be for just displaying what Google has recently index for a selected search term.