The popularity of Pokémon GO can be attributed to its demographic timing, mature technology, and summer release. Its genius UX includes one-tap registration with Google, a welcome tutorial featuring Professor Willow, personalized avatar creation, immediate gameplay after personalization, simple and accessible gameplay, request for data after experiencing the game, clear call-to-action requiring physical movement, and intelligent Pokéstop placement. The game's low barriers to entry and organic social sharing experience support its viral growth.