With 90M users, Viber adds group messaging

If you want to know why over-the-top communications services are giving cellular operators such heart burn, just check out VoIP and messaging app Viber. The app, available on iOS (s aapl), Android (s goog), BlackBerry (s rimm) and Windows Phone (s msft), has become a popular way for people to make free phone calls and send messages to each other.
How popular? Well, the company said it has now hit 90 million users, adding 20 million in just over two months. Those users are now spending more than 1.5 billion minutes on calls and sending over two billion text messages each month. And the messages should keep on flowing now that Viber is adding group messaging with Viber 2.2. available on iOS, Android and on the BlackBerry beta.
Group messages has been around for a while, so Viber is coming late to the party. But group messaging on Viber comes with a smart notification feature to limit new message alerts. There’s also a simple system for starting group messages, which can include text, photos and location.
The 2.2 update also includes an HD voice engine to improve call quality and reliability and the ability for users to add photos to their contact lists. And for Android users, Viber offers support for Arabic, Chinese, French, German, Hebrew, Portugese, Russian and Spanish with expanded language support coming soon to the other platforms.
Communications apps like Viber are scaring carriers, who are seeing some of their most profitable services undercut by over-the-top services. Viber’s fast growth will only ratchet up fears that users will reduce their dependence on voice and texting plans. It’s going to force carriers to get creative with pricing, something we’re seeing with the new shared family plans from Verizon (s vz) and AT&T (s t).