A new little feature is available at Pricenoia when comparing books, expanding the info offered by Amazon itself.
Until now, when looking at a book, Pricenoia listed similar products, using Amazon recommendations. We've now added a list of up to 10 other formats and editions of the compared book. You can find older printings, paperback editions of a hardcover book, editions in other languages, audiobooks, and some other interesting things.
Some of the books are available new at Amazon, and some of them are old editions that can only be bought used or from third parties (always at Amazon, of course).
For example: One hundred years of solitude, from Gabriel García Marquez.
This new feature uses the xISBN webservice offered by Worldcat. Great stuff!