Due to having surgery, I've had my bookshelf on 'hold' for the last few months.  During that time I have ordered and received books (to have to read as I recouperated!).

I have now taken my account off 'hold' status.  And I was wondering if all the new books that I posted that I received will automatically be posted on the main search page.

Not if they are on hold on your shelf.  When you mark a book received and it asks to put the book on your shelf it puts it on your shelf on hold.  So only you can see those books.  I think they have a little red x or something to distinguish them.  I don't use that feature.  I always post books from by the ISBN incase I didn't notice receiving the wrong book (it's happened).  I don't care about binding so unless I"m ordering an audiobook I don't usually double check the ISBN # when I receive a book.  But some people are really picky about that and I've reposted a couple of books that actually had a different binding listed then what I had gotten.  I just didn't notice at the time because I'm not particular about binding.  (yes I know I need to get better about that)

If you are talking about the books that are not on hold then they will show up under the books posted today page-I think even if they were on your shelf before you went on hold.