From Viber Media:
With Viber, everyone in the world can connect. Freely. Viber has more than 664 million users worldwide sending messages and making HD-quality phone and video calls over WiFi or 3G - for free. You can create group messages with up to 200 friends, share photos, video, stickers, links and more. There's no need to register - your phone number is your ID and Viber syncs with your mobile contact list automatically. If you want to make calls to non-Viber mobile and landline numbers, Viber Out credits offer low rates. You can also download Viber Wink to send messages that disappear after they've been viewed.
What's new in this version:
- More detailed info in group chats - see which of your friends have read and liked any message
- Camera improvements for video
- New Message Pop - no longer interrupts you when you’re in another app.