They laughed when I sat down at the piano, but when I started to play

Tested Advertising Methods, by John Caples (the writer of this headline), is one of the best books you can buy on how to write advertising copy.

At the bottom of the page, the article implies that the subject of the ad started to strum the piano, at which point I realized that they had reason to laugh; the subject of the ad was a professional comedian, thus: "They laughed when I sat down at the piano, but when I started to play they really bust a gut!"

So really, this was the story of a total success.

The repeated misuse of punctuation when quoting the headline undermines the story.

So what was this an advert for? Clicking on the advert itself just gives a 404.