Propaganda is the dissemination of information aimed at influencing the opinions or behaviors of large numbers of people.As opposed to impartially providing information, propaganda in its most basic sense presents information in order to influence its audience. Propaganda often presents facts selectively (thus lying by omission) to encourage a particular synthesis, or gives loaded messages in order to produce an emotional rather than rational response to the information presented. The desired result is a change of the attitude toward the subject in the target audience to further a political agenda.
Propaganda is the deliberate, systematic attempt to shape perceptions, manipulate cognitions, and direct behavior to achieve a response that furthers the desired intent of the propagandist.
—Garth S. Jowett and Victoria O'Donnell, Propaganda and Persuasion
Hat Tip to Guthrum
I think the above has come to the fore in the wake of the BBCs coverage of the counter protest against Muslim extremists in Luton. The BBC is a master of propaganda in this respect, mainly through omission and selectivitiy, but also through deliberate manipulation of the facts.