Facebook announced this week that 2 billion people - more than one quarter of the world's population - are now active users of the social network Mark Zuckerberg started in his dorm room 13 years ago.
Two decades ago, the notion that billions of humans would be connected by a single product would have been seen as absurd, unless the "product" in question were, say, a religious text.
Master your Facebook privacy settings
Did you know when your friends use their Facebook to log in to third party apps, those apps can access information on your profile?
But now Facebook has more adherents than any religion in the world, with the exception of Christianity - which it's poised to overtake in just a few years.
There are more Facebook users than speakers of any of the world's languages, according to Ethnologue, a long-running catalogue of the world's languages (exact counts are difficult, but with the vast majority of China's 1.3 billion residents able to speak Mandarin, it is the planet's most commonly spoken language).
Likes, shares, comments and friend requests are becoming the closest thing humanity has to a universal tongue.
Even more impressive than the sheer size is the speed with which Facebook brought a quarter of humanity into its fold. The network claimed its first billion users in 2012, just eight years after its inception. Adding another billion took fewer than five years.
By contrast, roughly 200,000 years elapsed between the appearance of the first modern humans and our 1 billion population milestone, which we hit around 1820. The quickest we've ever added another billion to our population happened between 2000 and 2012, when we went from 6 billion to 7 billion in 12 years.
Recall that Facebook just pulled this off in under five.
Facebook defines active users as people who visited the site or its messaging app through their desktop computer or mobile app in the past 30 days. For obvious privacy reasons, it does not make its user data public, so it's impossible to independently verify the company's user counts.
Any service growing that quickly is bound to experience some mishaps - recall that the tagline for "The Social Network," the 2010 movie about Facebook's rise, was "You don't get to 500 million friends without making a few enemies."
In recent months, Facebook has come under criticism for, among other things, suppressing conservative viewpoints, enabling suicide and murder, killing journalism, making people unhealthy and destroying democracy as we know it.
Caught up in the din of daily Facebook controversies, it's easy to forget that none of us -- not even Facebook -- have any idea what it truly means to have a quarter of humanity plugged into a single product, governed by a single set of rules and norms, uploading deeply personal information to a single database, making a single company the gateway between ourselves and the advertisers who want us to buy stuff.
You don't get to 500 million friends without making a few enemies
The Social Network
We just go with it, riding the tide of likes and shares into whatever Facebook's future holds for us.
The Washington Post