okay i recently received a book i had requested

now i see this message 

This book is currently on your Bookshelf on "Hold". Would you like to delete it from your Bookshelf?

can you explain what they mean by that?

In the help docs it says

When you mark a book received, the book will go onto your Bookshelf on hold, unless you choose for this not to happen at the time of marking the book received.

• This way they are easy to repost when you have finished reading them.

If the book is a gift or a keeper, you can say yes to the question you posted above and it won't be added to your bookshelf.  Otherwise, it will be on your bookshelf on hold until you repost it or delete it.

No one else can see it on your bookshelf until you unhold it.  It is not working it's way up FIFO or anything.  I personally prefer to only see my actual available for trade books on my shelf. 

You can sort your bookshelf so that you see your posted books, your books on hold, or all books.

I always remove the books from my shelf.  I too, like to see only the books that are actually available for trading when I look at my shelf.  Sometimes I don't know if a book is a keeper until after I've read it and very occasionally there is a "liquid mishap" that would prevent me from posting the book anyhow.  When I finish reading the book, I post it and all my swappable books go in the same place here at home so that I can readily put my hands on it when someone requests it.

When you go to "My Bookshelf" you can click on the button that says "See my Public Bookshelf" ... and those are your FIFO books.

I've got about 600 books on my bookshelf but only about 200 on my public bookshelf ... at least PBS makes it easy to tell the difference.

I always mark "yes" to remove from my bookshelf but I do add the book to my TBR pile and post them back to the system easily from there.

Cheryl

I keep them in my shelf in hold.  That way there are several different ways to find them and to post them.  When I want to see the active shelf I click on My Public Bookshelf because I like that format the best.

Ruth