I'm fairly sure, given the nature of the product, that Pokemon Go will play similarly to Niantic's other game, Ingress. It was stated early on in Pokemon Go's production that it would revolve around a similar principle and run on the same engine. For the uninitiated, Ingress is a game where literally getting out of the house and travelling the world is the goal. You are assigned to one of two teams and key places on the world map are labeled "portals". Imaginary wars are waged at portal locations to take control over them and eventually the entire world. Pokemon Go is very likely to run on a similar principle, but having some pokemon mechanics thrown in. It's very likely that you'll be able to find certain kinds of pokemon at different portal locations and that the types you can find there will change periodically. Like Ingress, special events may be held in big cities such as Miami, Los Angeles, New York, London, Tokyo, etc. These will probably be legendary pokemon events in the case of Pokemon Go. What Pokemon Go may add to what is very likely to be a very Ingress-esque experience is the ability to actually battle other pokemon trainers in passerby events and gain experience that way along with certain portal locations possibly being labeled as pokemon centers or gyms.
Meh... I should stop ranting. This is all theory anyway and it probably wasn't appropriate to post that here. XD I'm really into seeing what Pokemon Go will really be about considering all the hype that's been surrounding it since its announcement.
Well, still thanks for clearing that up 
