WhatsApp announced that it has passed the milestone of half a billion active users. This puts it well on track to meet the prediction of Facebook CEO Marck Zuckerberg, who said when Facebook bought the messaging app that it was set to be a billion-user service. At that time, in late February, WhatsApp had 450 million active monthly users. The company said it's been growing fastest in recent months in Brazil, India, Mexico and Russia. Its daily traffic has reached over 700 million photos and 100 million videos shared.
