WhatsApp may be the statistically best app we've ever made. It's a product manager's dream with its unparalleled addictiveness (DAU / MAU) of 87% and stickiness (M1 retention) of 86%, both #1 in the world while having the #1 most monthly active users for any non preinstalled app of 2.7B users. Here are the top 25 most used apps in the world by MAU on both these metrics. Some surprising observations: — There are now 15 1B+ user apps in the world, 8 by Google, 4 by Meta. — The 3 that aren't are…