Commenting on books through smartphone

[Martinsos]

Hi guys,
I am looking for your comments and ideas about following idea:
What if, while are reading a book, you could take a photo of the page that you are reading using your smartphone and see comments of other people that read that same page and commented on it? You could also write your comment, and other people can see it. This way you could easily share comments with your friends or book club members.

I got this idea because I often read the same book as my girlfriend, and we use chat or email to send comments about some part of it to each other, as we are reading it. That is somewhat complicated, as we usually read with different pace and maybe my comment is too early and so on, so I thought of this idea.

I hope this is the right place to ask, I am looking forward to your comments on idea!