Marketing, propaganda, and advertising are similar in many ways, but yet they also differ in ways as well.
They are all similar as they are all trying to introduce a view, or idea on to the person or group of people they are reaching out to. They are all distributed through similar methods, either the media, internet, or word of mouth.
Marketing is more of an idea and propaganda and advertising sub categories of it.
Propaganda is put on by the government and is normally trying to change somebody from the ground up. It deals with morals of a person rather than trying to convince somebody to buy or try a product. Many times propaganda is used in a negative manner, but I believe it could also be used to try to make the world a better place as well.
Advertising is performed by companies, and sometimes government. The difference between advertising and propaganda is, advertising is only really touching on mental issues and not dealing with or trying to change the way somebody thinks about life as a whole, just about one particular issue.