Surely you’ve heard of the dangers of subliminal advertising and how it has been banned in the United States. Well, it turns out that the insidious threat posed by these brief messages, secretly implanted in films may have been wildly overstated.
The entire public and political debate [about subliminal advertising] had been based on fiction, not on fact. … His [James Vicary, the man behind the Coke and popcorn study] fictitious study has become the stuff of urban legend, and is still referred to by those who believe that buying behavior can be influenced by subliminal messages. [page 132-3]
Subsequent studies have failed to find any increase in buying behavior after exposure to subliminal messages. So, your brain is safe from this supposedly insidious form of manipulation. Advertisers have to rely on other forms of insidious forms of manipulation.
Another fun tidbit from Quirkology by Richard Wiseman.