"Tenderfoot is a social platform that allows travellers to connect absolutely anywhere in the world. With Tenderfoot, you can 'stamp' and connect with your fellow travellers without Internet or phone network, using a unique QR code to move data and information between mobiles. No matter where you are in the world, simply open the app and stamp those you meet. The app then uses your mobile to record exactly when and where you stamped another traveller, enabling you to build your own personal travel community."
Would've liked to had this when I was travelling Australia for 6 months!
Startup Stash