Reverse auction type site. You name your price what you want to spend on an item. You put how long you are willing to wait time wise and basically "pre-pay"... If a retailer accepts your offer, you are charged immediately and your item ships from them. It is only authorized USA Canon dealers, no grey market stuff or anything. I was able to get the double-dip rebate before it was listed on any retailer (about a week prior).
Generally, it appears Adorama has been fulfilling almost all of the camera related offers.
Very interesting. Thanks for the info