Some marketing activity is aimed at creating demand, alerting people to a value proposition. Other so called marketing activity is aimed at delivering an offer, an important but very different activity to demand creation.
Consider the difference between most ads on TV, and the yellow pages. The former generally sets out to tell you why you should buy something, whereas the yellow pages is a list of places where you can go to get delivery.
Which leads me to all the all the banner ads on the web, those persistent, annoying and endlessly crappy pop-ups that appear. I have just upgraded from windows XP to Windows 7 as I replaced my laptop, not wanting the leap to windows 8, just a step too far, and have not yet figured out how to avoid the apparent thousands of pop ups plaguing my screen. None are likely to get my attention beyond wanting to strangle the silly bastard who is paying somebody to disrupt me in the belief that I will react positively to the disruption.
The old laws of supply and demand still work. The supply of space into which to place a banner ad on the web is infinite, so any price is too much, and it does not work, like an ad in the yellow pages does not work to create demand, just where to get it once you have decided to buy something.