I must admit that I have become a black-binder user at readings as well. I think this may have something to do with choral singing, which I also do. In fact, what I've always coveted is one of those choral-singing folders that actually has a strap on the back to hold it to your hand, which allows you to stand there grandly without benefit of lectern or stand and emote to the open air.

I am also thinking that the binder is a good substitute when, like me, you don't actually have a book to read out of...