This is a tiny side-project I did on [World Book Day 2015].
It was written to help me decide what book to buy next. I usually do that by looking at my GoodReads To-Read list and comparing it against amazon. This tool automates that.
It also allows you to post a link to a list of books (such as a discussion on Hacker News). It will find all amazon links in that post and compare the listed books for you.
You can see a sample result here.
Licensed under the MIT License