The voice calling service in Whatsapp will definitely change the instant messaging platform. As like other messaging service hike, Skype, Viber now Whatsapp users can also make a free call to its friends.
Recently Whatsapp have brought its messaging platform on web which is dubbed as Whatsapp Web. As the web version of the whatsapp is only available for android users and soon will be available for other users also.
Currently many of the sources reports that the calling features on Whatsapp is available in India but only for some users, and same thing have also claim by users also. Hope the service will soon going for everyone as it has been started.