LibraryThing is a social catalog for your book library. It is more oriented towards paper books and I wish it had more ebook specific support and it would be great if it would search Fictionwise. However, you can manually add books and tag them (like Delicious) as "ebooks" so it will work. Let's face it in books sharing the title is more important than the format. Still adding Fictionwise support would help add all those multi-format ebooks by smaller publishers.