I've heard some talk about it so I went to the site today. What exactly is it and is it worth my time to set up a shelf? Could I delete books from my shelf if they were a BC book and I passed them on? I'm afraid I just don't get it... :shrug:

I can't answer your questions, but here's the previous thread on it which you may want to look over too:
http://bookobsessed.com/index.php?showtopic=661

Thanks Cherie! I hadn't seen that thread before.