By way of Language Log, I came across the UnSuggester at LibraryThings. I now have a new way to waste away hours of my life on the internet.
The idea is that the user enters in the title of a book, and the UnSuggester will offer up anti-books, which are the polar opposite books. Interesting idea: not just the Amazon suggestions of “hey, other people spent their money on these titles, too,†but “hey, you should really avoid these.†But why bother with that? Well, homophily, that’s why.