I can see where this could be beneficial inside an academic environment. Reminds me a bit of my own college days where I would occasionally benefit from the comments left by previous owners when I bought used course textbooks.
Updated tech, naturally.
For pleasure reading, no thanks. As elcreative mentions, this should be something one actively chooses to participate in, not have stuff thrown at your personal ereading experience. I consider this intrusive.
Like most things in our modern tech age, stuff like this should be OPTIONAL, with the ability to use it or not. Then I would likely more readily embrace this kind of concept.
I paid for the ebook.
I paid for my computer.
I paid for my car.
etc, etc, etc...
Don't tread on me...
...unless I say it's OK...
