FaceTime
FaceTime has evolved so much throughout the years but was first created as competition for Skype. It now can do things no other app can, like detecting if someone’s using sign language to give them prominence during a call. And it all started in iOS 4.
Apple first introduced FaceTime back in 2010 as an easy way to make video calls to other iPhone and Mac users. Much like other features in iOS 4, FaceTime wasn’t available for iPhone 3G or 3GS because they lacked a lot of requirements – the main problem was that neither older iPhone had a front-facing camera.