The popularity is the most important currency that is used to progress throughout the entire game. It is generally considered to be the starting currency of the game, used to provide the game a pecular aesthetic. You can produce at lease one popularity point per click by the button "Generate 1 point", under the "Popularity" tab.
It is easy to see the popularity point in the game no matter the opened tab you are.
The number of popularity points varies between different game stages. In the early-game stage, the popularity point value lies around 10^18 (one quintillion) points. As the game stage advances, the number starts to increase exponentially. At the endgame, the popularity point value reaches above 10^3,000,003 (one millinillinillion or one micrillion) points.