Google Book Search now has the capability to add any book you find—whether they have the full text, a limited preview, or none at all—to a personal, digital collection. The official announcement states that you can rate, review, label, annotate, organize and (of course) search the full text of all the works in your library—apparently even those with limited previews. (I tried a selection of random phrases from The Great Gatsby, they were all found in the limited preview book.)
You can also share your library as a webpage, an RSS feed or an exported XML file.
The official announcement also mentions the ability to Explore Popular Passages, such as this famous passage from the closing of The Great Gatsby:
In the book view, a sidebar on the right side has a plus box to show all of the oft-quoted passages used in this book. The Great Gatsby passage, it notes, has been used in nearly 400 works. I’m quite impressed that the book was quoted 33 years before it was written. (Incidentally, this book was #1 in the search results for a phrase in this passage, [borne back ceaselessly into the past], while the book itself was #6).
The full view of Exploring Popular Passages shows other books that quoted this passage:
While this is very useful, especially for mass research, it has its limitations. In checking just a few phrases from Gatsby, I came across typos that were not only quite obvious (eg, o’dock instead of o’clock), but would make it difficult to find a passage if it hadn’t been scanned correctly.
And of course, the biggest drawback: much less impressive on your bookshelves.