I'm having difficulty seeing the value in this idea. It seems that Plurchase is going to be relying heavily on retailers to make this idea succeed. But, if I'm Zappos, Amazon, or any other online retailer, I don't want Plurchase -- or any other service -- hijacking my website via their own proxy, for any reason, and/or redefining my customer's experiences in any way.
And when the Plurchase team approaches online retailers and gives them ten reasons why allowing Plurchase to do this will ultimately help the retailer make more money, they are going to be met with a wall of skepticism, and rightly so.
It's always easy to rationalize how your ideas (that primarily benefit you) will benefit others too, but actually getting other people to agree with your passion and sign on with your business model is an entirely different story.
My 2 cents!