I just put a book on my WL.  It said it had 78 people wishing.  So I put it on my list, and my list claims I am number 90 of 90.  There are only 80 people wishing for a copy; how can I be #90?

The number that is shown on the book description page is not always accurate. I think that number is not updated as people add to the wishlist, but maybe updated once a day or something (I am guessing here...) The number on the wishlist is accurate (not taking into account people who might have their accounts on hold or who's wishlisted accepted & mailed  book goes lost in the mail, etc -- which is why sometimes it seems you are moving backwards).

It's possible that the number wishing on the book's page doesn't include those copies that are in the process of being accepted/mailed, but your place in the wishlist line does.

I've found that the number showing on the book description page can be as much as 10 listers different from what is listed on my WL.  Pat