how does amazon.com implement its smart book suggestion depending on previous purchases by customers ?

Hi,
I am sure you've all been to amazon and done some purchases there. I would like to know if anyone knows how they do this. Once you have purchased a book, they have a smart feature which tells about other books which might interest you based on purchasing patterns of other customers. Amazon.com is not the only site doing that, there are more and more sites implementing it. Does anyone know how they implemet that kind of feature ? Can it only be applied to books or to any other product ? Thanks all.

I'm thinking that they must query the purchases table to retrieve this info (which is to sugesst 3-4 similar books based on other customers purchase patterns) , but it will be a complex and intensive query and I don't think this is done in real time. Maybe they use some kind of procedure and run in batch mode and save the results ( 3-to 4 books) in a different table that is linked to the product table. Any ideas ? Thanks. Received on Sun Jul 15 2001 - 19:09:17 CDT