Zuckerberg gained three billion users and his organization gradually over about 10 years, not overnight.

The test is whether, as of March 2021, Zuckerberg's user base of about three billion people and his large organization were built up gradually over roughly ten years rather than suddenly. True: Facebook's filings show the company's user base (e.g. Family of Apps monthly users) at about 3 billion by early 2021, and show user and headcount growth accumulating steadily over roughly a decade. Mostly true: the gradual accumulation to about 3 billion holds, but the span differs somewhat from 'about 10 years' (e.g. Facebook was founded in 2004, about 17 years earlier), or the user figure is somewhat off (e.g. 2.8 billion for Facebook alone). Mixed: growth was gradual, but the user figure or the time frame is substantially off. Mostly false: the user base was far from three billion. False: filings show the growth was not gradual, which is not plausible.

Set before the research began.

1. E1 How Facebook grew from 0 to 2.3 billion users in 15 years | World Economic Forum World Economic Forum (article by Felix Richter, Statista, published in collaboration with Statista) · 5 February 2019

   “By the end of 2018, that number had grown to 2.32 billion people, meaning that more than half the world’s online population is using the platform dreamed up by a teenager in his college dorm room.”

2. E2 How Facebook grew from 0 to 2.3 billion users in 15 years | World Economic Forum World Economic Forum (article by Felix Richter, Statista, published in collaboration with Statista) · 5 February 2019

   “15 years ago, on February 4, 2004, 19-year old Harvard student Mark Zuckerberg, along with some of his classmates, launched a little website called Thefacebook.”

3. E3 Facebook is about to hit 2 billion users. Here’s a closer look at the rise of the social giant | World Economic Forum World Economic Forum (Forum Agenda, John McKenna) · 10 May 2017

   “2016 1.86 billion users. Facebook Live is rolled out to all users, and Messenger passes 1 billion monthly users.”

4. E4 Facebook is about to hit 2 billion users. Here’s a closer look at the rise of the social giant | World Economic Forum World Economic Forum (Forum Agenda, John McKenna) · 10 May 2017

   “1 million are active on the network by the end of the year.”

The evidence shows Facebook launched in 2004 [E2] and grew to 1.86 billion users in 2016 [E3] and 2.32 billion by the end of 2018 [E1], which fits gradual growth. None of the items gives a user figure for early 2021, so they do not show whether the user base reached about three billion, which the criteria require.