Often while traveling, it seems that there’s no place immune from a wireless connection. Hotels, cafés—even buses allow you to connect with the world using your cell phone, laptop, or notebook. It’s been many years since I’ve heard someone make a call from an airplane using those seat-back phones: “Hey, you’ll never guess where I’m...

SIM cards and top-up cards. Photo: Karl Baron /Flickr Creative Commons The situation: you're out and about in an exotic land. You meet some cool travelers, open-minded and fun. You all fervently promise to meet up later that night. What happens? You show up on time, but your new friends are nowhere to be found....