Already, NDL started a project called "Digital Library from the Meiji Era," by which many books and other materials of Meiji era (1868 to 1912) and after are provided for free. Although most of them are in the public domain, it is trying to obtain a license from the author or quasi-license from the ACA commissioner (ACA commissioner may grant a quasi-license on orphan works) and increase the stock in the library.
The project ACA recently announced is an experimental project where some of these books are to be distributed in a Japanese online bookstore. Some of the reasons that Digital Library from the Meiji Era was not very easy to use for many people are that (1) they are basically just scanned image files and (2) they are only available at a certain site run by NDL. Because of the first feature, it is not easy to find a book we are interested in. They are only searchable by the titles, not by a keyword search of the contents. In addition, because of the second feature, only those who are interested in visiting the special site to search can obtain the books. When a person wants to find a book and make a keyword search in a digital bookstore like Amazon and iTunes, these books cannot be not found.
Unfortunately, the project's main purpose is not to improve both of the issues the Digital Library from the Meiji Era currently has. Rather, the main purpose is to show a model of digital publishing to other entities on how to lawfully publish digital books and thus encourage other companies and organizations to start publishing digitally. However, at least it is a good thing that some of the works in the Digital Library from the Meiji Era are distributed in one of the major digital bookstores in Japan (Kinokuniya). Also, the positive feedback to the project may promote further improvement of usability issues of Digital Library from the Meiji Era such as the difficulty to search and not being available in major digital bookstores. Therefore, I understand that this can be a milestone for possible improvement of the Digital Library from the Meiji Era that may lead to resolving the existing problems.
One of the thirteen works to be distributed in the project is "Hentai Stories (Ero Ero Zoshi)" written by Kiyoshi Sakai. The reason is that this is one of the most popular book in the Digital Library from the Meiji Era, which may or may not draw the interest of some of you.
February 3rd, 2013 : Mr. Tomita, running Aozora Bunko, a free digital library of public domain books in Japan (similar to Project Gutenberg), wrote an article on the project.