Flesch persuaded his publisher to try a direct mail campaign. Within only seven months they sold over 40,000 copies of his book by mail. From a testing and tracking viewpoint, you might say the mailing bombed. After all, everyone didn't send in order forms. But those same people took the order form and went into the bookstores.
Successful marketing involves an orchestrated marketing strategy.
You can't put up a web site and then complain that you don't get sales. You have to market that site. But you also have to realize many people will learn of your book because of the site and then go get it in a bookstore. I do that all the time. But rather than order online or call a toll-free number, I shot over to the closest bookstore and bought the book.