Earlier this summer I was planning my 16 hour drive to Colorado and knew that podcasts wouldn't be enough. I needed some longer stories to keep me engaged for hours at a time. I heard about Audible many times over the last couple years but it took me until this summer to finally signup.
One of the things that's surprised me is how effective their marketing is. They maximize every piece of data they have. I've been especially impressed with their wishlists. I started adding books to my wishlist so that when I finished a book I could reference my list to buy the next book. What I didn't realize was that they would use that data to get me to buy the book today.