Violet this week announced what it says is a "unified API for anything on the internet." The idea is to make it easy for people to buy whatever they want, no matter where they see it on the web, without requiring them to backtrack or hop through ecommerce sites across the internet.
Consumer Notebook just launched their API at PyCon. The Consumer Notebook site allows users take products and add them to lists and grids. Lists, as you’d expect, allow you to group common products. For example, gift ideas for friends, or books you’d like to buy. Grids provide a way to rank and compare a set of similar products. Perfect for planning your next cell phone upgrade, or deciding which trampoline best fits your lifestyle.
Consumer Notebook [is a] product comparison site that combines the best features of Open Comparison, Yelp, Consumer Reports, and Pinterest.
The API is REST based, and provides data in JSON format. Currently the documentation only references read access to the principle resources: Users, Products, Lists, and Grids (a comparison of products).