Thanks for the feedback and yes I agree that is something we're considering especially allowing others to embed similar drag-n-drop tools on their site to share onto Minus.
We already have an API documented and ready but just not yet released. If anyone is interested in testing it, feel free to shoot an email over to john@min.us and i'll send it right over!
Some tech specs on Minus: http://blog.min.us/2010/10/14/minus-tech-spec/
(PS: We were inspired by Glen Murphy's Dropmocks design and really hope to make Minus into a universal sharing tool with wider compatibility and support for documents, music, video and more in the near future. In the works = desktop app and firefox/chrome extensions ^^)
Cheers John