Snapchat
Not an appropriate time to video chat with a friend? That may be too bad. The friend can reach you without you accepting the call so long as you're active in Snapchat's app.
The instant video chat feature is essentially a way to call someone without the phone ever ringing. CEO Evan Spiegel tells The Verge that he wanted the feature to resemble running into a friend on a street corner - you're both in the same place at the same time, and you strike up a fun conversation.
From The Verge's description of the feature, Snapchat's new video calling isn't a two way street. If a friend sees you on the app, they can video message you and their face will pop up on your screen without your permission. If it's an inopportune time, the recipient can flick the video screen away with his or her finger.
From The Verge's Ellis Hamburger:
Video chats don't have to go both ways. When you tap and hold on the blue button, within a couple seconds your face lights up on your friend's screen. There's no ringing, and there's no 'answer call' button to press. You can talk as much as you want while your friend listens, and if you want to show them something you can drag your finger upwards to activate your rear-facing camera. If your friend wants to join in, they can tap and hold on their screen to start sending video your way. There's no "end call" button either, naturally. You just lift up your finger.
It's all part of Snapchat's strategy, "Here," which strives to make all users feel like their friends are constantly present an attentive.
"We're trying to get rid of these weird boxes that we put media into and get to the essence of conversation - that we're both here," Spiegel tells Hamburger. "The essence of conversation is not which media format we choose to talk to each other with, so we don't differentiate between snaps and chats. It's just someone wanting to talk to you."