Springer has a site that displays a bunch of information for a search, including a map, a list of results, a keyword cloud, institutions and publication dates. It also allows you to search for OA articles only, in the "show all options" search.
Shown is a screenshot of the top of the page for a search on 'akerman'.
There's more information down the left hand side of the screen below the part I cut out.
The Download PDF link takes you to SpringerLink.
You'll probably have to click several layers down (several zoom levels) before clicking on a particular "pin" will give you a popup saying something like "x articles from y institutions" followed by an institution list.
The search results list doesn't change as you zoom in on the map.
Despite the name, you can also search by topic, or by combinations of criteria (an example given is Map migraine articles published by authors from the USA). The default starting screen shows the locations of the last 100 articles published.
This is a great example of making your existing data work harder, as Lorcan says.
I don't know exactly how they're doing it (one could guess some reasonably straightforward term extraction). There's not much info about how it works in their AuthorMapper blog.