One billion people check WhatsApp every day. Not every month -- it hit that number way back in early 2016 -- but every single day. The Facebook-owned chat app has announced the milestone number in a post thanking its users, though it was also mentioned in passing during the company's earnings call. Zuckerberg mentioned during the call that Facebook's own Messenger app has reached 1.2 billion monthly actively users (MAU), but WhatsApp still has more patrons in that regard at 1.3 billion MAU. Taking those numbers into account, 76 percent of people who use WhatsApp don't go 24 hours without firing it up on their devices.