I once happened to attend a RubyConfIndia talk by C42's Steven Deobald who said:
Lots of people have been asking how isbn.net.in works, so I rewrote that weekend hacked-up code into something nice on top of Rails 3 and other goodies.
A while back, I released a side-project called http://isbn.net.in - a simple tool for comparing book prices in India. I received lots of feedback, suggestion...
I had an itch - I wished there was a simple way of deciding whether to buy a book and where to buy a book. So I created http://isbn.net.in