I have a product design company and we use dropbox for sharing files with colleagues and customers around the world.
I'm interested in developing a web-based (PC and Mobile) application that links to dropbox. The application will be a hub for file uploads, guiding users through drop-down menus and free-text entries. This is important so that the documents in dropbox have the appropriate metadata tags. The web application will also be used to access and view the doucments based on the metadata tags.
Can the dropbox API developer create something like this? Are there any examples of existing applications?
This certainly sounds like something that one could accomplish using the Dropbox API. (I'm not sure what you mean exactly by "metadata tags" though. Dropbox doesn't offer a way to store arbitrary metadata for files, but if you're just referring to metadata stored in the file itself, or on your server, that would be fine of course.)
Anyway, to get started, I would recommend looking at the tutorial and sample apps for whichever SDK you want to use, or the SDK for whatever language you're most familiar with: