We built a new site in Drupal. Actually it's really a tool more than a Website. It's called SNI.PS (http://sni.ps) it capturescontent you capture: text, video (YouTube and QuickTime), images, and flash objects and gives RDFa embed code to reuse it while maintaining attribution to the original source AND subsequently copied sources. For example if, I copied it from you and some one copied it from me. Both you as "origin" and me as "copied" are retained. If you use a rel-license we capture that and bring that along with the embed code.
It can also capture content behind walled gardens. We even made a cool Facebook handler to "free your images" for use elsewhere:
http://sni.ps/screencast/facebook
There is a start of an API. SNI.PS is free to use and does not require users to log in to use the product. We hope it is useful. If you have ideas on how to make it more useful, we are eager to improve it.
Hopefully you will find it an interesting use of Drupal and maybe you will find the tool and API useful, too.
Best,
