(The Open Library):
What if there was a library which held every book? Not every book on sale, or every important book, or even every book in English, but simply every bookâ€”our planet’s cultural legacy.
First, the library must be on the Internet. No physical space could be as big or as universally accessible as a public web site. The site would be like Wikipediaâ€”a public resource that anyone in any country could access and that others could rework into different formats.
Second, it must be grandly comprehensive. It would take catalog entries from every library and publisher and random Internet user who is willing to donate them. It would link to places where each book could be bought, borrowed, or downloaded. It would collect reviews and references and discussions and every other piece of data about the book it could get its hands on.