If you see a group of kids walking around looking at their phones, odds are good they are chasing monsters playing Pokémon GO. The app available on iPhone and Android devices mixes the real world with the virtual world of Pokémon, and it’s no exaggeration to say it’s taken the world by storm.

The game was made available earlier this month, and quickly started making headlines. It also got a lot of people like John Samuel Knight outside getting exercise.

“It’s right there in the middle of the road,” he says after finding a Pokémon by Petersburg Motors.

At the time, the game w...