Plain folks propaganda is a technique used to portray a person as an ordinary citizen to their audience. This technique is commonly practiced by politicians.
In politics, most politicians are wealthy, but they strive to present themselves as ordinary people to the citizens. They do several things to portray themselves as salt of the earth, common people. Some wear ordinary clothes to avoid sending flashy messages to the people. When visiting certain regions, some politicians dress like locals to show they can relate to the issues of the area. Some politicians use simple language so they can communicate more effectively with average citizens. They also try to participate in normal activities, such as bowling, beer drinking and eating fast food, like average people do.