Share 'The impact of Book Trailers on Book Sales?'

Is there value in creating a book trailer? In promoting a novel months before it's released? I'm curious about this marketing tool which seems to be popping up everywhere. Working with a talented friend, I was able to create a wonderful video - a way to introduce my story, and have already experience over 20,000 views on YouTube. Wouldn't it be great if this translated into sales? I'm curious as…