VOIP app Viber has 200 million users

"Mobile-first messaging and communications platform Viber has landed on the desktop.
Originally available only on smartphone platforms like Android, iOS, and others, Viber has added a desktop client that seamlessly interoperates with its mobile apps and now enables video calling for the first time.
The result is a combination of just about every kind of communication you could wish for in a single client: mobile text-like messaging, audio, and video. Which means that not only is Viber competing with mobile messaging platforms like the massive WhatsApp, it’s also competing with existing VOIP giant Skype.
And it’s got a few advantages on both sides.
With its new desktop client, Viber can seamlessly transfer calls between mobile and laptop, handy if you need to get out of the office in the middle of a call. It seamlessly syncs contacts between devices, silently and continuously, and it shows your received and sent messages on all your Viber-equipped devices.
[...]
The VOIP communications company with its roots in mobile announced today that it has hit the 200 million user mark — startlingly fast growth for the young company which had 140 million users just in December. That’s perhaps not surprising, as the company is growing at mobile speed — it was the ninth most-downloaded app on Google Play as of March, 2013."
Source:  VentureBeat, 7th May 2013