Growing at 30k new users each day, Nimbuzz has got to be the fastest growing mobile VoIP service at present. The partnership model that the start-up has pursued (partnering with operators and social networks) seems to be bringing in good number of users that could be turned into paid customers at some point.
There have been a couple of interesting announcements lately from the company. One that carries significance is the O2 deal. O2 has launched Toshiba TG01 handset with Nimbuzz preinstalled across all O2 channels in Germany. Nimbuzz is also on the brand new Micromax handsets and Spice Mobiles in India, with more handsets to follow in Europe soon.
In terms of the operators Nimbuzz has signed up, only O2 and Tata Indicom have been announced so far.
Nimbuzz works on Wifi and 3G for straight VoIP. It also offers Hybrid VoIP on 2G and 2.5G networks. This works in over 50 countries where Nimbuzz connects its users via a local access number (using their operator minutes) to the buddy they are trying to reach via their VoIP servers.
Nimbuzz is able to provide phone number based VoIP service in partnership with Voxbone that supplies them the telephone numbers. However within an operator partnership model Voxbone enabled service is not offered since that would potentially be in competition with the operator in question. We are however likely to see phone number based over-the-top VoIP services on mobiles soon.