I just received a promotional email from amazon which starts like this (translated from German):

"We've noticed that customers who bought "The Dresden Dolls [Enhanced]" by the Dresden Dolls also like the Dresden Dolls."

I wonder whether Jeff Bezos has got a patent on this extremely witty piece of software. It solves equations like "1=1" in no time. Most likely a highly parallelized jewel of software running on some Cray.