Love the concept. I currently use retailmenot's firefox plugin for finding coupons for the site I'm already on; I probably am more likely to use something like that because 1) I almost always order from 3 or 4 main sites (amazon, newegg, thinkgeek, and grudgingly dell.com), and 2) price comparison shopping never seems to be as accurate or rewarding as that $10 off coupon you never knew about