I probably know this person, because they'd need my number to make the call.

Over 22 Million people world-wide already use oo Voo for video chat and voice calls on mobile and the computer. Call oo Voo contacts mobile to mobile, or mobile to computer.

ONLY SUPPORTED ON: HTC Evo 3G & 4G, Samsung Epic, Samsung Galaxy S GT-i9000, Samsung Galaxy Tab 3.0, and T-Mobile My Touch 4G, Dell Streak 5, Nexus S and Galaxy S 4G.

In that way, video calling feels old-school before it's ever even cool.

Even if everyone decides to get down with video calling, Google needs to get tons of people to download the app if it is to become part of the world's messaging lexicon.

Almost everyone already has a video-chatting app, be it it Snapchat, Facebook Messenger, Skype, Viber, Face Time, or even Google's own Hangouts.

It's hard to imagine millions of people embracing an app that does the same thing those apps do, especially when people don't do that thing much anyway. Once Google fixes its few bugs, it will be everything a video chat app should be.

Etiquette guides, pro tips, and unwritten rules govern the interaction.

Video also isn't conducive to modern communication.

More releases on mobiles and tablets with front-facing camera planned soon.

Kakao Talk (Android, i Phone) Kakao Talk is a phone number based messenger service that allows i Phone and Android users anywhere in the world to chat one-to-one or in a group for free.

Everyone texts, usually with emoji and GIFs and little punctuation.