At the end of December 2019, Zoom's busiest day had about 10 million daily meeting participants, free and paid together. Then came the pandemic. On 1 April 2020, Zoom's CEO Eric Yuan wrote that in March the service had passed 200 million daily meeting participants. More than 90,000 schools in 20 countries had taken up Zoom's offer to help children keep learning remotely. He wrote that supporting the influx had been the company's "sole focus" for weeks.
Three weeks later Zoom announced 300 million. This is where the story gets a footnote. Zoom's April 22 blog post called them "daily users" and "people". The Verge noticed that the post was later quietly edited to say "300 million daily Zoom meeting participants", and Zoom then added a note admitting the error. In a statement to The Verge, Zoom said it had "unintentionally referred to these participants as 'users' and 'people'" and called it "a genuine oversight".
The difference is big. A daily active user is one person, counted once a day. A meeting participant is counted once per meeting: as The Verge put it, if you join five Zoom meetings in a day, you count five times. According to The Verge, Zoom had not published a daily-user number at all.
None of this makes the growth small. Going from 10 million to 300 million participants in about four months is a thirtyfold jump in meetings joined. But the number on the blog measured something different from what the headlines said.
- About 10 million daily meeting participants, Dec 2019
- More than 200 million, March 2020
- 300 million, April 2020: participants, not unique users
- 90,000+ schools in 20 countries had taken up Zoom's schools offer by 1 April 2020
Why it matters: Before you size a system, or trust a metric, ask what exactly is being counted. "Users", "sessions" and "participants" can differ by several times, and capacity follows the one that creates load.