Pretty much everything you want to know about Bounce Back Offers in this handy TP Blog post http://blog.touringplans.com/2014/07/22/disney-bounce-back/
And yes, I know that this is the second daily tip for today. I got busy yesterday and failed to post one. So sue me 
Booking BB before leaving is a good tip but find it a bit disappointing that a relatively recent article on TP has outdated (and some just bad) info in it.
What info is bad/outdated?
Did you notice that awesome photo in that post?