Sure. I built a webapp that uses Dropbox as a global, read-only storage that is accessed on average just once a day per app instance. At midnight, or at startup, each site synchronizes its local file list with a common dropbox site.

Yes, there are many other ways this could have been done, but it was built to be administered by non-technical people who at least understood how to upload files to Dropbox and they have access to all of Dropbox's file management tools. A massive chunk of functionality that we didn't have to build out!