Many apps have been trying to take on Skype — among them Viber and recently, messaging app Line_which launched a cheap calling service. Now another app has surfaced, called Ringo. What's notable is that the app doesn't need Internet connection for you to make calls. Essentially, this means that the Ringo app has the ability to route calls just like the way a regular carrier does, so "calls are not affected by fluctuations in internet connectivity that often lead to audio delays, loss of quality and dropped calls." The company also notes that the phone number you make your call...