This is such an interesting topic!
I thought that scope was an interesting topic to be brought up, specifically how it related to where the content is going to reside and who will be in charge of the actual digitizing (scanning, uploading, saving, etc).
Thinking about this, I re-perused The Digital Public Library of American Concept Note from March 2012. I think that the statement made in the concept note regarding the development of “an open, distributed network of comprehensive online resources that would draw on the nation’s living heritage from libraries, universities, archives, and museums in order to educate, inform and empower everyone in the current and future generations.” is interesting, and extremely relevant. Currently the scope is so large that no single entity is able to take control of all aspects of the project. While it seems more feasible to have all these respective types of organizations create their own DPL and then eventually combining them all, there would still need to be standards created for digitizing, naming conventions, standardizing/updated file-types, uploading, storing, backing up, and archiving the various resources. Who would be in charge of the creation of these standards – perhaps a steering committee made up from the different backgrounds.
Classification conventions are increasingly important simply because of the sheer amount of content – if you’re going to have materials for self-educators, k-12, through postdoc researchers available there will need to be a variety of ways to classify so that someone sitting at their home could figure it out (unless you plan on having a cadre of librarian’s on-call to help and answer questions from users.
All in all, I think that DPLA is a wonderful idea – I just think that there needs to be the infrastructure in-place so that materials are accessible, information is not lost, and that people are able to use the library.