Would you want a "director's commentary" for a book?

Have you seen the "Public Notes" option on the Kindle?

It allows Kindle users to make their book notes and highlights available for others to see. Which means that any Kindle user – including authors – can "opt-in to share their thoughts on book passages and ideas with friends, family members, colleagues and the greater Kindle community of people who love to read."

I haven't tried it yet, but surely that means an author could add background or extra details to a book, much in the way that turning on "director's commentary" in DVD extras works with a film. I think it's an interesting idea. What do you think? Is that something you'd be interested in reading? (Authors: is that something you'd be interested in writing!?)