Simple. Personal. Real Time Messaging.

WhatsApp Messenger is a cross-platform mobile messaging app which allows you to exchange messages without having to pay for SMS. WhatsApp Messenger is available for iPhone, BlackBerry, Android, Windows Phone and Nokia and yes, those phones can all message each other! Because WhatsApp Messenger uses the same internet data plan that you use for email and web browsing, there is no cost to message and stay in touch with your friends.

In addition to basic messaging WhatsApp users can create groups, send each other unlimited images, video and audio media messages. WhatsApp Inc. was founded in 2009 by US citizens Brian Acton and Jan Koum (also the CEO), both former employees of Yahoo!. On February 19, 2014, Facebook announced it would be acquiring WhatsApp for US$19 billion, in what will be its largest acquisition to date.

Create groups, send each other unlimited images, video, audio messages,
share location and contact.

WhatsApp has crossed half-a-billion user mark. In a 22 April 2014 blog post, WhatsApp had over 500 million monthly active users, 700 million photos and 100 million videos are shared each day, and the messaging system handles more than 10 billion messages each day.

Extraordinary growth in Whatsapp users compare to the other social networking apps users.

Source: http://www.whatsapp.com/