Politicians have always used language, as in speeches or campaign advertisements. They use common themes to develop their political positions in terms familiar to the voters. Politicians become experts at using the media With the rise of mass media in the 19th century they made heavy use of newspapers, magazines, and pamphlets, as well as posters. The 20th century brought radio and television, and television commercials became the single most expensive part of an election campaign. In the 21st century, they have become increasingly involved with social media based on the Internet and smartphones.