With most dating services, live human interaction is usually the last thing that happens. It's what you get if that back-and-forth messaging actually leads somewhere. In Hotline's newly launched service, however, it's not just prominent... it's mandatory. The mobile app requires that you have a 5-minute voice call with your prospective partner (thankfully, without using your phone number) before you can message them. It's a scary concept if you're shy or hate calls, but the hope is that you'll quickly find out whether or not the real person is as interesting as their profile.