Yesterday, I decided to buy a book on Amazon I have always wanted to read.  Amazon kept recommending other books and topics that "I might like"... and oddly enough they were right!  Amazon recommended several books that I've heard and wanted to read, but had since forgotten about.  Needless to say, I walked away with a slightly larger bill than expected. 

I've been using Amazon and Pandora for a while now and they both seem to know what products I want to buy, books I want to read, and music I want to listen to.  I think there is something to be said for these engines and that they might very well be the norm in the future. 

I don't know the all inner workings of these technologies and collaborative filtering, but I interested in learning more about them.  Time to reread the old lecture notes from CS410 at UIUC.