I am trying to post the book The Vanishing Act of Esme Lennox. When I look it up on the wish list, it says that 13 people want it. When I go to post it, it doesn't say that anyone wants it. I realize that the publishers are different, but it is the exact same book. Why does it matter what publisher I post it under? If people want this book, I want to be able to send it.

It's by ISBN. Some people really do a particular ISBN of a book, which I guess is the case here.

You could post it - the people who have WL'd it will probably get e-mails that say 'Similar to Wish' announcing your book to them.

There is also a thread in the bazaar for people to post WL books with different ISBNs.  You could post there also once the book is on your shelf.

You can also add a tag to the wished-for ISBN saying "available under ISBN XXXXXXXXXX"

Keep in mind that sometimes people want a specific binding type for a book.  So if the WL line is for large print or audio and yours is a paperback that is already available in PBS-they probably don't want the paperback version.  If I post say a mmp that's not highly posted in PBS and I see a WL for hardbacks, I'll tag the hardback with "posted under ISBN xxxx" and usually it's ordered pretty quickly-although some people collect hardbacks. 

Also the email will not get triggered for a PBS generated ISBN.  So if your book has to be posted w/o an ISBN it won't trigger the email. Also some people turn that email notice off.  Like me.  I frequently WL audio versions of highly posted books by James Patterson and some others.  The emails were out of control so I turned it off. I have so many books to read-if i miss out on a different version of a print book it's not tragic to me.

I like the suggestion of the tag on the book you can see.  That really makes a tag group-friendly.

Tagging the WL version with the posted versions ISBN works.  I do this eveyrtime I post a dif version of a WL book and it works everytime.  But then I research that my version is a similar binding and doesn't have a bunch of copies posted already. If there's already several copies of my version posted then I assume they really want the version they have WL.  Some people collect specific covers of certain authors especially if it's a series. I don't do it if the WL version is audio or lrg print.