Popular mobile messaging service WhatsApp crossed another
major milestone recently. The company CEO announced on Twitter that
WhatsApp is now service over 600 million monthly active users.

The CEO was quick to point out that it’s active users, that is,
people actually using the service everyday, and not just registered
users, which would be a bigger number but a lot of those people won’t
actually be using the service.
This makes the milestone all the more impressive and shows once again
just how popular WhatsApp is. The service may not be popular in America
but in the rest of the world, and especially in developing markets,
WhatsApp has an unwavering fan following, especially since the service
is available on practically every mobile platform, including low-end
feature phones. For example, 60 million of WhatsApp’s current active
users are from India.
The company was recently
acquired by Facebook for $19 billion, although it has remained unchanged and operated independently despite that.
Source