Subliminal Messages - How Can They Be Used?

Subliminal messages are those that enter our brain without us being aware of them. There is no question that the brain operates at a level we are aware of, and one that we are not. It is this fear of the unknown that concerns people. Could we all be turned into mindless drones doing the will of those who feed us subliminal messages? Or, are subliminal messages a positive step toward self improvement?