SockPuppet_9_5 writes: I help run a website promoting a collective of authors and have a form for automating their submissions, so as to then provide "Buy This Book!" links to Barnes and Noble and Amazon. The problem is with the changeover from ISBN-10 to ISBN-13. While the changed ISBN numbers work well with BN.com, Amazon.com links with the new ISBN-13 in the link often won't work if there's a duplicate ISBN-10 number also assigned to the same book. Even searching out Amazon with the ISBN-13 number often produced no results to books currently on the shelves — you must know the older ISBN-10 number for Amazon to reference the book correctly.
We've figured to tell our submitting authors to use the ISBN-10 number if it's provided, but I'm curious: While the publishers probably initially submitted the book to Amazon with the older ISBN-10 number, why is it that Barnes&Noble don't have a problem with this situation and Amazon does?