Interesting, similar to https://www.filepicker.io/
Our goal is for users to be able to connect directly to their online content, and we're working with Dropbox, Box, Google Drive, Skydrive, Facebook and others to make this happen.
It also seems like Dropbox is encouraging a different use case, in that the links they provide by default are Dropbox share links that route back to Dropbox, and even the direct ones expire after 4 hours. With Filepicker.io, we want to be a more complete filesystem solution, offering things like store to S3, read/write on the URLs, conversion, etc.
To the cloud!
Keep it up!