add a feature to allow people to tag books as duplicates, then you can combine the results
Julia Steinberg commented
There are also cases where the book is listed by series and by individual title.
"The Wars Of Light And Shadow (8) – Stormed Fortress: Fifth Book Of The Alliance Of Light" by Janny Wurts,
"Stormed Fortress: Wars of Light and Shadow: Alliance of Light Series, Book 5" by Janny Wurts, and
"Stormed Fortress (Bk. 5)" by Janny Wurts
are all the same book but have separate listings, each saying it is available at one site.
Seems like a good idea, some books have the authors names slightly differently e.g.
Robin / Dickinson Peter Mckinley which should be Robin Mckinlry and Peter Dickinson.
Also seen site where they "correct" the spelling of the authors names!