"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 book—a key part of our planet's cultural legacy."
These folks plan to do just that with the help of everyone in the world using a customized wiki to build The Open Library. Talk about dreaming big. I'll have to keep tabs on this project and see where it goes. They have already hooked up to the Internet Archive's book scanning project so that you can read the full text of all the out-of-copyright books. They also located a copy of the Library of Congress card catalog, phoned publishers and asked them for their data, created a brand new database infrastructure for handling millions of dynamic records, wrote a new type of wiki that lets users enter structured data, set up a search engine to look through it all, and made the resulting site look good.
The site is an early technology preview, and many things are still in flux or not operational. In the meantime, you may want to take a guided tour. Thanks to Mike Kudela for sending me the link!