Whatsapp is a powerful cross-platform messaging application that allows you to exchange messages within and across networks irrespective of your location and using whatsapp group is easier to reach users at ones.
Whatsapp has revolutionized instant messaging concept. It has the ability to enable users to share images, videos and even allow free calls within the application network.
This suggests that you can make free calls from your whatsapp application to another user of whatsapp on another number with paying for it.
As well, organizing users in groups ease the communication process.