What to read next website

From Senga Watson, James Hargest College :

Many of you may already have come across this cool “what to read next” website but I’ve only just recently discovered it. I think it’s great! http://bookseer.com/
I wondered if it might even be useful in finding similar books for themes (wouldn’t always work mind you, but could be a good place to try) where you already have one suitable book but you need others.