No one could have predicted this result 20 days after launch.
Google's Play Store listing for Pokémon Go changed this morning, revealing the game had just crossed the 50 Million downloads mark only 20 days after the game's limited release in a couple of countries. Since that day, Niantic has slowly made Pokémon Go available to more countries as it scrambled to increase server capacity to handle the explosive popularity of the game. At the time of this writing, Pokémon Go is still not available worldwide but it's quite close. This week will likely see the end of this slow global rollout, meaning more bursts of users are on the way.
To put this install base into context, Pokémon Go now has more installs than Google Fit, Google Inbox, and the Google Cast app. It's on track to pass Instagram on Android at this rate, and has not yet been in existence publicly for an entire month yet. It just goes to show that if you work hard and keep a brand alive and interactive for 20 years, you too can create a cultural phenomenon that sweeps the globe.