KFC is once again trying to outwit all those DVR users out there. If you watch next week's premiere of "American Idol" you'll see a new campaign for their Buffalo KFC Snacker that challenges viewers to spot the difference between this year's spot and last year's version. The first 10,000 people who figure out what that difference is and correctly identify it on the KFC website get a $1 coupon for a free Snacker. This follows two previous efforts last year to foil DVR fast-forwarding by embedding messages in the ad that could only be viewed when slow-watching and hiding a punch line in the commercial.