Propaganda is a form of communication aimed towards influencing the attitude of a population toward some cause or position.
While the term propaganda has today acquired a negative connotation by association with its most manipulative examples, propaganda in its original sense was neutral and could refer to uses that were generally positive, such as public health recommendations, signs encouraging citizens to participate in a census or election, or messages encouraging persons to report crimes to law enforcement. Today terms such as "public relations" are often preferred.
In its more negative sense propaganda may be seen as biased, selective, false, encouraging an inappropriate particular synthesis, and/or intended to produce an emotional rather than a rational response. The purpose of a propaganda message may be open and obvious. However, propaganda may also be more subtle and inserted into, for example, popular movies and television series.