So I posted a wishlist book and it went to XX.  I went to XX wishlist and saw she also wanted another book I had so I sent her a PM about it.  The WL book timed out and ended up on my bookshelf and I received no reply to my PM.  About 5 days or more after listing the book originally, I get a reply that she would like the book.  But the book was requested by someone else, which I did not realize as I had not accepted it yet.  I had her add the ISBN of the second book which I posted to her.  Now I see she has an RC about no cracked spines which when I posted book two, I did not know about.  Now I had thought the first book was going to her and it had no RCs.  Once she accepted the second book I saw her RCs.  Anyway, I got a PM today ten days after the book was delivered in answer to my PM asking if she got the book.  She says... Yes I got the book.  I suppose I should update my RC to say no creases.   I did not realize that cracked and creased spines were not the same thing.  Am I happy with the book?  No.  Is the spine cracked?  Technically no.  But I am marking it received normally because it is my fault for not realizing they were two different things..

This is the first time someone was unhappy with a book I sent and I have mailed out 2349 books.  I am scrupulous about checking books over before mailing them and if there is a doubt, I PM the requestor.  That book was rather large and whoever read it creased the spine to read it; this was a bought used book.  A cracked spine is one where the book separates and you can see the spine, no?   

I would take cracked to mean the same as you, spine visible between pages (previously referred to and much debated as "cleaved").  A would just shrug it off and maybe err on the side of caution if you see another RC regarding "cracked" or one from this same member as given their reply, I'd be hesitant to send as well.

Also, if I read your post correctly, you went to her WL and saw she had another book WLed that you had and you PMed her asking about the second book.

 A suggestion that might help with the frustration in the future - whenever I have either an unpostable or additional WLed book that I haven't posted on someone's WL when they've ordered a book from me, I will send them a PM and describe what I have and give them a date a day before I plan to ship the original book - somethink like - "You have ordered book XYZ from me.  I see on your WL you are also looking for book XXX.  I have an unpostable copy (has water stains, or whatever) or I have a copy of XXX that I haven't posted yet..  I will be shipping book XYZ on BBB.  If I do not hear from you by CCC I will presume you are not interested.  Thanks."

This way I'm not waiting for someone to reply to a PM (I've found that sometimes it's several days before they even read the PM) and I haven't lost out on shipping the original book as I usually ship books twice a week.  Good luck in the future.  Pat

The requestor let the first book time out with no response so there was no option to say she'll mail only the first book on x date if she doesn't get a response. So that wouldn't have worked in this case,

I think this person is just reallly picky.  I read my books carely and they still get spine creases sometimes even when I bought them new.  I don't prop them open or spread them wide or anything.  Paperback books just tend to be cheaply made now. 

Thanks to all of you; I appreciate your valuable input and advice.  I will be a little more careful when it comes to certain RCs, I guess.  I think it is very difficult not to have spine creasing on a book of well over 400 pages, IMO.   Thanks again for your help.

The receiver is correct. There is a difference between a "cracked" spine and a "creased" spine. She knew this, but decided to send you a boo-hoo poor me PM anyway? Why? I think she was looking for a pity credit.

Lisa, I thank you for your comment.  I think in my heart this is what I thought she was doing but was not sure.  That book is wishlisted by a number of members and would have been taken easily.  Personally I do not care for books that have cracked/cleaved spines so I do not buy or post them; I donate them.  That way I do not have problems with anyone saying the book is broken.  I believe that the conditions for swappability do not mention cracked or cleaved spines.  Does anyone know? 

This is what the postability guidelines include:

Binding:

• Must be intact, with no separation on the inside or outside of the book
• If the book tends to open at a particular page, this is OKAY
• Small amount of fraying or denting at top or bottom is OKAY

Which I read to mean the spine can't be cracked.  To me creases are perfectly acceptable (and actually expected) in used paperbacks.

edited for spelling

Thank you, Laura.

Here's some good images.

Creased spines - there are lines on the outside of a book, but the inside is fine - doesn't fall open to any particular page.  These are postable.

Cracked spine - http://i2.photobucket.com/albums/y4/rubberducky102760/2762798875_d3dec5c5e0.jpg This is postable.

Cleaved spine - http://i2.photobucket.com/albums/y4/rubberducky102760/8_299.jpg - not postable 

Rhonda, thank you for the photos!  That really helps.  My book was nowhere near as bad as the first picture as the book would not lay on its spine like the second photo.  I am going to keep these images for future reference.  Thank you!

I think the official term for what she was doing is "complaining".  Since she had no official problem with the book, it's her problem, not yours. I would just ignore it and forget about it.