This isn't an idea, it's an execution. It's a funny video clip for jack-in-the-box, no one else. It has absolutly nothing to do with the thousands of we-are-here and other completely off target companies sending these around. Viral marketing is about developing a strategy to respond to a want your market has.
Sith Sense and
Subservient Chicken are brilliant examples of viral marketing and utilizing the ability of sharing contagious content with friends. Guaranteedtrafic is a guaranteed failure as are the people that use it. The purpose of advertising and marketing is to find a unique way to get people to use your product/service, not to laugh. If they laugh while exploring the features of your product than its a great campaign. But there is no call to action from receiving a funny clip in the mail that has nothing to do with the site plugged below it.
Wendy's and Carl's viral network will only work if the message is consistent and on strategy with what they are currently trying to sell about their products. That recent rejected paris hilton spot got tons of attention from the media and the web because it got banned for her looking like the $lut she is. But it is definitely not going to increase sales at Carl's.