(Undated) — Pokemon Go is now the biggest mobile game in U.S. history. Survey Monkey reports the reality game attracted almost 21 million users as of Tuesday in the United States. Previous record holders were Draw Something with 16 million users and Candy Crush with about 20 million. Within 24 hours, Pokemon Go hit number one on the App Store and after three days, the game had attracted more users than Twitter. Pokemon Go attracts players to public locations to capture cartoon characters on their smart phone screen.