Above is a screen shot from the collection page for the United States Marriage, 1733-1990 index from FamilySearch. The orange area represents it's coverage between 1803 and 1812. If you search for marriages in Florida in 1805, this collection will not show up.
These new collection pages are beautiful, fun, and useful. We have already identified and fixed several bugs in our indexing process now that we can easily visualize our data. It's also useful for researchers to understand the coverage of particular collections. For example, when searching for records in Eastern New Mexico, it's easy to see why collections from Texas appear in the results.
These new collection detail pages are available from the search results. Just click the "Details" button to open that collection's detail page in a new tab.