For those of you who haven't acquainted yourselves with the Amazon's "customers who bought this, also bought this" feature, you might find Your Next Read intriguing, but for those of you who have, don't bother heading over there.
Your Next Read teasingly offers to select your next reading choice based on the book you just read, provided, of course, that you want your next book to be similar to your previous one. When I typed in The Last Town on Earth, the site suggested a couple of books on flu (woot), Into Thin Air, and a memoir that looked completely unrelated. Alice I Have Been brought up a few historical fiction books, Tracy Chevalier's newest amongst them, and a Lewis Carroll biography. No surprise that these books also came up in the"customers who like this, also bought this" section of Amazon.
The suggestions are based on Amazon buying patterns, rather than on similar theme, genre, or topic. Had the site suggested Brooks' Year of Wonders (a novel of a town that quarantines itself to prevent the spread of plague) for The Last Town on Earth, I would be willing to give it more credence, but clearly this is just a fancier version of what Amazon already provides.
The site does allow folks to suggest books, so perhaps it will grow more interesting and intelligent in time, but it's pretty limited right now.
To find your next read, I would stick with Amazon, a well-read friend, or this blog's recommended lists.