With everyone’s different data plans, staying in contact with friends without burning through your bill can seem pretty impossible. The creators of WhatsApp cashed in big time when they provided the service that allows friends to stay in contact regardless of their service plan. You can send as many messages as you want to as many friends as you want free of charge. It’s not limited to words either. You can send videos and pictures, too from wherever you are on the globe. No wonder Facebook paid $19 billion to get in on the action.