The limitations of backpropagation learning can now be overcome by using multilayer neural networks that contain top-down connections and training them to /generate/ sensory data rather than to classify it. (...) much better than previous approaches
Researchers believe that comparing products, rather than rating them on an absolute scale, will lead to algorithms that better predict customers’ preferences. ----------------- http://horicky.blogspot.com/2011/09/recommendation-engine.html