When you walk down the street any given day, you are flooded with cognitive noise from every direction: secret commands flashed at you as quietly and undetectably as possible, bending your mind to their will. You get into the car and turn on the radio, and your ears are filled with hidden directions nonstop; you go home and watch TV, and there's a constant surge of obscured, cloak-and-dagger but direct orders being beamed continuously into your brain. If you notice it, it's just a flicker out of the side of one eye, or a brief bit of catchy tune - and an hour later, you have no memory of the mental invasion, only an inexplicable urge to go out and do... whatever they tell you to...
Welcome to the world of marketing. No, this isn't some kind of bad sci-fi plot; it's a thriving industry that helps to change a product's image. To fully understand marketing, we must look at the types and nuances of marketing, how marketing works, and the different types of marketing in action.

There are many types of marketing; advertising, generally speaking, is the promotion of something tangible; this includes goods and services. Propaganda, another familiar form of marketing, is almost always designed to promote an idea. It is distinct from advertising on the whole in that it seldom, if ever, relies on cumbersome appeals to logic, working directly on more direct and powerful emotional appeals. However, there is often significant overlap between these categories; both will often visually connect two otherwise unrelated concepts in order to reinforce a desire for a product or idea. An example of this in advertisement is a Honda commercial which shows photographs of cars and their owners which resemble one another paired together and claims, at the end, 'It must be love'. This demonstrates a key aspect of marketing: subtlety. It is usually possible for skilled marketers to deliver their message without directly stating it, and when the message is directly stated, it is never unaccompanied. It is very important in both types of marketing to make the message clear, but no more clear than necessary; otherwise, the command given can be more easily recognized and ignored. It is best to let the audience 'fill in the gaps'.

This leads us to how marketing works. In psychological terms, marketing works by influencing congnition in the direction the marketer desires. In other words, it's designed to try and change the way you think with subtle messaging and association. The same sensory input occurs, but how we interpret it changes. Particularly successful and pervasive marketing is meant, in some slight way, to change the way in which we see the world. These persuasive methods include appeals to reason, but more often appeals to emotion, through connotation, implication, and symbolism. The best advertisement wants to make a believer out of the audience, and in propaganda appeals to reason are seldom used except to back up an emotionally charged claim.
One important thing to remember is that advertisement is not, by itself, very powerful. It's more of a nudge than a shove. That's why it's important to create repetition of a message, often through short, catchy slogans or jingles, long-term ad campaigns, and a constant general message.
Methods of advertisement that have been shown to work particularly well are appeals to emotion - optimism, flattery, fearmongering; essentially, any emotion that can be harnessed - and pseudological appeals, such as through a bandwagon effect, appeals to authority or celebrity, or logical (as opposed to emotional) association.
While it might be the most famous thing related to marketing and certainly one of the top ten things people think about in relation to it, subliminal messaging is actually not anywhere near as effective as you might think. When the subliminal perception effect was first discovered, there was a fear that this technique of broadcasting messages invisible to the naked eye but persuasive to the subconscious brain would lead to such things as movie theatres inserting 'BUY POPCORN' or 'DRINK COKE' into subliminal flashes to increase concession sales. In one telling experiment, a Canadian television company ran 'subliminal messages' on a certain program. When viewers were asked what effects, if any, they felt, many said they felt hungry or thirsty - because of the scare over POPCORN and COKE in theatres - while the message was actually 'TELEPHONE NOW'.
But who needs subliminal advertising when advertising over the threshhold of detection is just as effective and invisible? Advertisements and propaganda are both as old as the written word, and can debatably predate it through 'word of mouth'. Graffiti found in the Roman village of Pompeii advertised products and candidates in local elections. while we might not have invented marketing, we've certainly taken it from an art to a science. The first advertising company wasn't established until 1843, and it's only been recently that companies have existed to create adverisements in addition to simply buying the space to print them. 

Before we look at advertisement as it is now, we ought to look at propaganda. It's often debated whether propaganda - marketing of ideas - came first, or advertising - marketing of products - did. But it must be said that modern advertising owes a lot to the experiences of propagandists in the first half of the 20th century. These men had to mobilize a populace to fight some kind of enemy, sometimes internal but more often external, to rally behind the flag and gear up for huge conflicts. The first World War was the first war in which  entire societies were mobilized to fight common enemies. Unfortunately, the print advertisement had not yet reached its golden era, and the revolutionary propaganda of the era consisted of falsified reports - more or less lurid coffee table books that would get the common man outraged at the other side's atrocities. Overall, propagandizing for the war on the whole was still done on a primitive, premodern basis. But propagandizing for concrete actions such as greater production or investment in war bonds did see significant development in posters and broadsides. This was an artful use of associations - associating harder work with success in the war, or associating making potentially risky loans to the government with a sense of patriotic duty, as in this Russian propaganda poster asking, 'Do you help our glorious army fight the enemy?' Propaganda would develop at an astonishing pace before and during the second World War, as both alliances realized they had to mobilize their entire countries to fight their enemies. In the US, flying bullets, wounded soldiers, and an ever-present Uncle Sam urged workers to invest 10% of their paycheck in war bonds to help the war effort, and all were urged to do all they could in the face of the Japanese and German enemies. Other propaganda would proclaim superiority of the nation, of its beliefs, or of its people; this kind of propaganda was designed to ensure that war exhaustion would not hurt will to fight. But once the war was over, the huge market for propaganda no longer existed.

Or did it? The end of World War 2 in America coincided with a big surge in advertising due to a bunch of new companies. As anyone who ran a fast food joint in the 50s could tell you, there wasn't really all that much that set one hamburger place from another... except for reputation. Advertisement, an ofshoot of the aggressive propaganda developed in the 30s and 40s, helped produce that reputation. Creation of a distinct brand and franchise also helped. McDonalds grew into an empire by being consistent, repetitive, and capable of forcing themselves into the market. With the rise of mass media, commercials have grown more difficult to predict, and the advertising industry, continuously working to sell us products we might not otherwise have given a second thought, have to move at breakneck speeds to keep ahead of an increasingly ad-flooded populace. Some consistent tactics include advertising using celebrities, which can sometimes lead to amusing situations in which an advertisement actually outlasts the celebrity which makes it meaningful.

This provides a relatively interesting contrast with the rest of the image of marketing - something quick, a swift punch to the brain that leaves you dazed and confused, hopefully in the right way - repeated enough times to push you into doing whatever the marketer wants. But nowadays, marketing campaigns never die, they just fade away; searching through the Internet, videotapes, or research on certain types of ads will reveal words, images, and voices as critically dated as propaganda urging us to do our part to do in Hitler. If you've watched the classic movie Back To The Future, you might remember some commercial cross-ins from 1985 which caused culture shock in 1955: Calvin Klein underwear, which we still wear twenty years later... and Pepsi Free soda, which didn't outlast Reagan. Marketing is part of our culture, and with its introduction into modern movies and other forms of entertainment, it's being immortalized forever. It's everywhere, and you can't escape it. The amazing part isn't that they can broadcast a movie about a man's experiences in war in between reverent paeans to 'the power of Cheese'; the real wonder is that we never notice... until that cheddar down the aisle starts looking tempting.