answer:It uses both your phone’s camera and the GPS to make Pokemons appear in locations known as Pokemon Spots. My 18 yr old daughter up loaded it on Wednesday, the day it was released, and has been loving it. We were at AT&T Park for a Giants game Wednesday, and she was laughing at grabbing Pokemons off the infield. And yes, if three people are at a Pokemon spot, they can each interact with the Pokemon. That came up in a story I was relating to her about an old man grabbing them in front of jr high kids, and she said, “that must be a false story, because it doesn’t work like that.” disclaimer: I have not played it, I am only relaying what my kids have told me and what I have read on line.