Bing Cashback (previously “Windows Live Cashback”) has been one of my consistent favorite things Microsoft puts out. It actually worked simply and well. Basically, you found the product you were looking for via Bing's shopping site (or at least found the merchant you wanted there) and Bing paid you a portion of the cut they got from the merchant.
Sadly, Cashback is coming to an end:
We are writing to notify you that the Bing cashback program will be discontinued, and the last day to earn cash back on your Bing Shopping purchases will be July 30, 2010.