The ginsu knife of sales letters

"If you can't make the effort to make your post understandable to someone not in your domain, why should I assume you're saying something worth reading?"

He assumed the domain of people familiar with ginsu knives is roughly identical to the domain of people who have ever watched an infomercial in the past two decades.

Obviously, there are people all over the world for which this assumption is false. However, globalization is arguably incomplete until every single human on earth has at some time thought: "Gee. Cuts through a boot. How tired would I have to be for this advertisement to work?"

The Ginsu knife is a product most famous for the activities that were used to promote it. It was made famous through a series of long-form advertisements in the 1970s and it is claimed paved the way for the modern day infomercial with its use of quirky catchphrases, comical quips, and urgent call to action, including the phrase "how much would you pay...don't answer" and "but wait, there's more". ~via Wikipedia

The target audience understands that very well.