Testing how value propositions, USP and other webdesign elements can impact the botton line of your business is compulsory for e-commerce and other online ventures.
A preliminary step must be accomplished firt, competitive analysis.
The best resource that i found so far has been published by MarketingExperiments.
This framework is really not a high level grid of analysis but you can use it as a mezzo lens to analyses comepetitors.
