Many of my wishlisted books have been published under several different numbers.  Do I have to wishlist each one separately, or does the FIFO go by title?  If I wishlist only one of them and it comes in under a different number, would I still be in line?

Thanks for any answers you can give to this perplexing question!

FIFO goes by ISBN so you will need to WL each ISBN that you are interested in.

If there are a lot of ISBNs for a particular title, I often check Amazon to see which are the versions that Amazon carries (those are the ones that are either in stock OR have the most number of used copies). Those tend to be the US ISBNs.

It is not uncommon for British (or canadian, or Australian) ISBNs to be listed in the PBS database, for example (because people do obtain books from re-sellers in those countries and then list them here) but in many cases, wishlisting those ISBNs is a waste of WL spots.. I usually confine myself to ISBNs that are or have been for sale in the US.

If a book with an odd ISBN gets posted, and no one is wishing for that edition, all the Wishers get an email saying a similar book has been posted. I've gotten a number of those for hardback versions of books I want in softcover and occasionally for older books, which often have lots of updates.

I've won one or two where I wanted the offered book and got there before other wishers, but it doesn't happen often. It can be fun to get that "A Book Similar to One On Your Wish List Has Been Posted" and see if I can beat the rush! Usually, I don't, but when I do, I feel like I won a prize.

Checking Amazon is good, and I also go by any info on when the book was last posted. Sometimes, a couple are being posted regularly, so I keep both versions on my WL.

The short six digit numbers are the PBS only one time use, such as to post a book with a different binding than the main version.  It would be better to skip those ones.  

Although I do recommend searching for them with the book browser.

They do it by ISBN because some people only want hardcovers, some only want audiobooks, some only want large print etc...,  If they did it by title then people would end up getting offers for versions they didn't want.  It's easier to have those who don't care what edition they get wish for everything.

I do what Sara does unless I have a lot wish list spots open.  I don't like large print editions so I skip wishing for those unless it's a super rare book and I want to get in every possible line.  I don't waste WL space on the PBS created ISBNs.  Also if I'm tight on WL spots, I'll go through and remove some editions that have no sign up being posted in the last year, unless of course all the versions of it haven't been posted in the last year.

Also whenever I want to order myself some books, I look over my WL and aim for a book that has many editions taking up spots or isn't posted often. 

Thanks to all for the great ideas!  I had no idea what to do!