I've got a book that I received this past World Book Night. It's marked on the back cover that it's not for resale and doesn't have an ISBN number on the cover. There are two ISBN numbers listed inside the book, one for a hardcover and one for a paperback. As far as I can tell, the only difference between my copy and the regular Berkley paperback is that it's marked for World Book Night and the inside of the cover tells about WBN and lists the organizations involved.

Can I post this under the regular paperback ISBN?

Thanks!

Books that are given away at book conventions and fairs are okay. So World Book Night would fit into that category. 

I agree that the book you describe is postable and shouldn't be a problem. However, because the book is marked "not for resale", you need to be sure that it is a not an ARC (Advance Reader Copy) as these are not postable on the site. See the Help Center doc What is an ARC?

I found the following e-mail posted in this topic: http://www.paperbackswap.com/World-Book-Night-Books/topic/295283/. 

Type:    Email to Member
Date:    8/9/2014 7:35 PM ET
Subject:    Re: Your PaperBackSwap Feedback...
Message:    Dear J.,

Thanks for writing in to ask about this. World Book Night books are distributed free with the purpose that the books will be given to people who would not otherwise read them. The books do not have ISBNs.

They could be postable, dependable on the circumstances. Posting them right after getting them from World Book Night would not be in keeping with the spirit of WBN. If you received the book from someone else and want to share it via PaperBackSwap, that makes more sense.

Keep in mind that the books don't have ISBNs printed in them, and so they can't be posted using ISBN listings - they have to be posted using the "post a book without an ISBN" option.

Have a great day and happy reading,

The PaperBackSwap Team

Per the PaperBackSwap feedback e-mail above,If you received the World Book Night book from someone else, you can post it using the ISBN found on the inside of the book (unless it is an ARC).  Per the PaperBackSwap feedback e-mail above, if you received it from World Book Night for distribution, then posting it here would not be in keeping with the spirit of World Book Night; which I interpret to mean it should not be posted here. 
 

Thanks for the feedback! I think I"ll just donate it to the senior activity center, since it's not a book that's in demand.

I appreciate the replies!