The Roman city of Pompeii was destroyed and buried by the eruption of Mt. Vesuvius in 79 CE. The preserved city allows archaeologists, historians, and Classicists to examine materials far better preserved than a ‘traditional’ archaeological ruin.
The graffiti on the walls of Pompeii are famous for the content and vulgarity. However, scholars now believe they served another purpose: communication. Perhaps working as an early, non-tech, “social media.” Property owners may have had control over the political messages written on their walls.
“The current view is that any candidate could have chosen any location and have their ad painted on the wall. After looking at the contexts, this would not seem very likely. The facades of the private houses and even the streetwalks in front of them were controlled and maintained by the owner of the house, and in that respect, the idea that the wall space could be appropriated by anyone who wanted to do it seems unlikely.” - Eeva-Maria Viitanen
To learn more about the political ads and their role at the city of Pompeii, see the article posted at Scientific American.