Propaganda was an untruthful message that was used to influence the opinions of a populace.
For six months in which the Monks dominated Earth in the late 2010s, the Twelfth Doctor presented propaganda broadcasts featuring the Monks' version of human history. Among other influences, the Monks took credit for saving Earth from the Daleks, the Cybermen, and the Weeping Angels. However, the Doctor was merely acting as such to gain the Monks' trust so he could overthrow them. The propaganda could also be drowned out by listening to a tape the Doctor made that spoke over the projected message. (TV: The Lie of the Land)
While posing as the British Prime Minister Harold Saxon, the Master, while aboard the Valiant, enslaving everyone on Earth to subjugate to his word and rule, by using the Toclafane to oppress the populace and using the Archangel Network to broadcast a drumbeat signal to brainwash the world. (TV: Last of the Time Lords) The Master had setup the network while running for Prime Minister, but made it a subtle drumbeat in people's phones, laptops, televisions and computers to indoctrinate everyone in the United Kingdom into liking and voting for him in the general election. As the Tenth Doctor said, it transmitted a message: "vote Saxon, believe in me" that affected everyone who heard it, even Jack Harkness and Martha Jones. (TV: The Sound of Drums)