As a marketer over time you learn that nothing is pure and most things are for sale. For example I can make an ok ad to sell me ebook and watch it convert at about 1 - 1.5% all day long. I then can change that ad AND ONLY THAT AD and watch my conversion rate more than double.

Something like

Dominate Search Engine Rankings.
Insiders Guide Packed with Secrets!

works rather well. People are more likely to buy from a strong ad then a weak ad. They see what they want to see and taste what they want to taste.

Stronger presell = greater desire = final sales letter page reads better = more sales.

Call it anything you want, but really good copywriting is just sparking an emotion and exploiting it. Nothing more. Nothing less.

Where does the sale stop though?

I have had to rewrite my ebook to sound more politically correct because of partnerships I intended on making. Still completely honest, just not as blunt.

Fark Sells Content Space as Unlabeled Ads
What the fuck is that? How is that for cutting edge? source

Company Manipulates Own Search Results
Others take this a step further though. Yahoo! is renting text links which will manipulate their own search results. That is extremely sketchy when you consider that they also use human editors to edit their search results.

Marketer makes wedding a Marketing Expo?
Corey Rudl that is just tacky...