I think all advertising is "subliminal", but perhaps not in the sense that you mean.
You see happy/sexy/powerful/sucessful people in advertisements using such and such a product. Do you actually say to yourself "Oh look at that person, that could be me if only I had that product"? No, of course not! Nobody actually believes what they see in advertisements! We know they are only false images presented to us. We aren't that gullible!
...yet we still buy the product?
It is in this sense that advertising is subliminal, not by flickering up words, or playing sounds backwards. It is done by presenting to us an image, which is stored in the back of our minds and becomes associated with a particular product.
__________________
|