I have not really tried any games that are multiplayer yet, so not sure how that works exactly. But can two iphones, not in the same location (like across the country from each other), identify each other, connect and sync data to play a game against each other? Or do you have to either have a web app or local network to play games against someone else on different devices.
I am not exactly sure what you are saying, but in order to play with someone from around the world, you have to be online. And in order to play with someone next to you, you have to be in the same local network. I hope this answers your question!