The concept is quite similar to BookSeer, which we featured here back in June. However, where Book Seer derives its recommendations from Amazon’s and LibraryThing’s recommendation engines (which tend to give you more books by the same author), What Should I Read Next? offers a more eclectic selection.
There’s certainly a bit of static — FileMaker Pro 7 Bible is not much of a response to having recently read the memoirs of Alan Bennett — but it’s definitely more stimulating than the “read more by the same person” approach. You can optionally register with the site to build your own reading list and improve its recommendations.