In just two months since Facebook dropped $19 billion to buy WhatsApp, the five-year-old mobile messaging app on Tuesday announced its its active user base has grown to more than half a billion people. On February 17, the day it was acquired by Facebook, the company said it had 450 million monthly active users worldwide and over 320 million daily active users. “In the last few months, we’ve grown fastest in countries like Brazil, India, Mexico, and Russia, and our users are sharing more than 700 million photos and 100 million videos every single day,” WhatsApp said on its blog.