An interesting blog post entitled Negative Cashback from Bing Cashback, which illustrates how, allegedly, that using the "Bing Cashback" deal isn't that good a deal at all. Basically if a site sees you coming in from Bing with the cashback bonus, it gives you a raised price so the discount you get back actually is just a bit off an artificially raised price. Allegedly. Interesting to see if this gets any traction.