Some people have criticized that digital libraries are hampered by copyright law, because works cannot be shared over different periods of time in the manner of a traditional library. The content is, in many cases, public domain or self-generated content only. Some digital libraries, such as Project Gutenberg, work to digitize out-of-copyright works and make them freely available to the public.
Genre publisher Baen Books has made many of its titles available electronically through the Baen Free Library.
See List of digital library projects for an extensive listing.
Alternate definition:
The Digital Library is:
While the first definition is focussed on ebooks, this is much more general. Information objects can be anything expressed in a digital format: books, journal articles, maps, picture, sounds, etc. The important thing is that, like a "regular" library, the Digital Library is organised to store and make accessible the objects it contains, but the storage and retrieval methodologies used differ in being "electronic".