I have been working on a sort of file/media sharing tool, which is location-based service. File sharing & location, yes, they're applications that similar to Bump. But basically, this applications don't require to 'Bump' at least. Once you run it, it just works to find out shared file nearby.
If you're interested in location based file sharing, just look over them. URL of web site is http://www.fountainproject.com