The recommendation system is broken, however the social networking features can surmount it.

For example, my Goodreads "friends" are people who like the books I like. There's no social obligation. FFS, I unfriended my sister. My high-school friend who only reads YA fiction: he was unfriended years ago.

My favorite goodreads friends are a half-dozen people I've never even met, but I agree with their reviews. When they give a book 5 stars, I check it out.

That's the key to Goodreads. If Amazon can't figure out how to make better recommendations, they should look long and hard at how the social graph beats the star-ratings.