WhatsApp CEO Jan Koum made the announcement on his Twitter account:
Now serving 600,000,000 monthly active users. Yes, active and registered are very different types of numbers…
— jan koum (@jankoum) August 25, 2014
He is quick to note (understandably) that “active and registered users are very different types of numbers.” This is because many other messaging apps only report registered users to boost their user numbers, even if those registered users are not necessarily still using the app on a regular basis (i.e. active users).
Unlike most competitors, WhatsApp offers a no-compromise experience for virutally all mobile devices and operating systems
While user counts don’t necessarily mean a certain app is better (WhatsApp has fewer features overall than virtually all of its competitors), it does nevertheless show that even Facebook, which owns WhatsApp but also competes with it by way of its own messenger app, will be hard pressed to surpass WhatsApp in overall user count.
One notable advantage that WhatsApp does have over its rivals is that it offers a no-compromise experience with virtually all of its features available on virtually all mobile devices and operating systems — something that the vast majority of its competitors cannot lay claim to.