Activating this plugin will make the search search media attachment as well as posts or pages.
This would allow you to share resources by just uploading sensibly named files.
For example this test blog has several images of ferrets and a pdf named ferret uploaded to the media library. They are not in any posts or pages.
If you search for ferret you get this page:
Search Attachments Plugin to see the search results.
These search results are coming from the name of the uploaded files.
They can also come from the files description, if you add text there: Mustelidae