Subliminal Advertising: Effective?

I've always been interested in the subject of subliminal advertising, which basically asserts that a hidden message can be read by a subject's unconscious and influence their decision making on a product, and how it affected consumers. The above ad is an older ad yet classic example of the subject by the Absolut vodka makers, who constantly come up with creative ads. This one, however, titled "Absolut Subliminal" is almost a counter-subliminal ad as they are almost alerting to the reader that the ad has to do with something subliminal messaging by including "Subliminal" within the copy. The whole concept of subliminal advertising doesn't work unless the viewer isn't aware of what is going on! Thus, alerting them to subliminal activities defeats the purpose. However, the ad also features the words "Drink Absolut Vodka" spelled backwards within the ice cubes if you look closely at the light shadings. The image on the left is the actual ad that ran, while the image on the right is an enhanced image with its contrast changed in order to see the ad better. Honestly, I could not see the words in the real ad until looking at the enhanced image. They were not prominent enough. Does subliminal advertising work? I've tried to find out. Two years ago in my AP Psychology class, my group did our final presentation on that very subject. We created our own little mini experiment by mixing subliminal images with normal ones in a slide show for a various product and surveyed other classes to see if they noticed a difference. The experiment was guided by our teacher and we found that there was little to no correlation between the students being more apt to favor one product over the other based on the ads. Most students didn't even notice the subliminal messages and wrote that they thought the experiment was a waste of time on the feedback survey. Does that solve the debate? No, of course, but from my experience, subliminal advertising such as shown above does not seem to work.