Ha! When I need to get work done, I tell myself "Don't Do It!". My favorite is "Don't drink that beer until you're finished with your work!"
Yes, these ads are very effective. We see it in IM a lot, too. "Don't buy this until ... " Usually an affiliate with a bonus.
Weird how the human mind works. We have to read reviews before we buy something, but just seeing something that says 'don't', first, we are whippin' out our credit card.