Video: Nimbuzz vs Viber

Nimbuzz is the free call and messaging app for the connected generation. Nimbuzz combines the powers of the Internet and mobile communications into one, and lets you meet, share and connect with family and friends on any mobile device.
Viber is a mobile app that provides free international calls and text messages to other Viber users using 3G or Wi-Fi. Uses your existing contact list - check out which of your phone contacts and friends is already on Viber so that you can call and text them for free.
Face to face in the news:

2014 - Mobile messenger Nimbuzz acquired by New Call to fight Viber

Nimbuzz, an early mover in mobile messaging that currently has 200 million+ users was acquired by UK-based provider of low-cost fixed line and broadband services New Call (for $175 million). Nimbuzz was a breakeven business, and expects to be profitable in Q4 with voice services, mobile ads and stickers driving revenues. Nimbuzz was founded way back in 2006 in the Netherlands, but it found a lot of traction in the India, South East Asian and Middle East/North Africa markets. Nimbuzz came online well before the first iPhone and the app explosion that followed on iOS and Android, and the subsequent rush of messaging apps like WhatsApp, Line, WeChat, Viber, Kik, Facebook Messenger, Snapchat (and so on) — all of which offer consumers the promise of connecting them to friends in more interesting and cheaper ways than telcos’ messaging services ever did.