Price -- How much will it cost a person to stop (or take on) a certain behavior? In social marketing, price isn't just a question of dollars and cents. It can also be a question of time (i.e., how long will it take me to find a trash can?), or how much of an effort a behavior change will take. A life-long smoker may be the first person to admit that smoking is an extremely expensive habit, but may still say the costs--in terms of effort, or possible weight gain, or nicotine withdrawal--are too high. He just can't quit.
Smokey Bear and his admonition, "Only you can prevent forest fires," when seen alone on T.V., are again just an advertisement. But taken in context of all of the work done by the U.S. Forestry Service, the result that emerges is a social marketing campaign. Smokey is trying to change a particular behavior (being careless with fire); his message is targeted at a specific audience (six to ten year olds), and information he provides (on commercials, on the Internet and elsewhere) overcomes two major barriers to children being careful with fire: ignorance and also the scientific, "it's no fun" barrier. Further, the message is supported with information provided to parents at the campsites, making it more likely they will provide reinforcement to the message. That's social marketing. It uses targeted marketing, reinforcement, and it reduces barriers--three key elements missing from the two examples above.