OS notifications, in-game notifications, constant asking to send messages to one's Facebook friends, basically a barrage of nagging in order to propel the game into everyone's life.
Being a casual game a descriptive tutorial is necessary so that anyone who picks up the game can understand the mechanics fully. Farmville 2 does a really good job at this with the first hour of the game basically being a full on tutorial that explains all of the basics in an informative manner.
The theme of this clicker game is of course communism, where the player tries to build their empire through utilizing potatoes. While you will eventually move on from using potatoes as the main source of income, the fact that such a silly theme exists for a large portion of the game shows off the sense of humor the creators have.