Recommender systems are nothing new. The list of books on the side of this blog is generated by LibraryThing which has a very nice recommender system. It analysis your library and then recommends books contained in other users libraries. Amazon tends to use recommender systems and recommends customers that people who bought a certain book also bought certain other books.
This is nothing new. But when I came across Amaznode I was pleasantly surprised by the graphical representations of their recommendations (which are based on Amazon). The system creates a web of books which others have bought. This is a cute way of representing data.
