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## Confidence Checks for Our Napkin Estimates
We can do some confidence checks using public stats about YouTube!
YouTube reports having two billion users and "billions of views" per day (https://blog.youtube/press). Assuming "billions of views" refers to somewhere between 2 billion and 9 billion, we can guess each user averages out to somewhere between 1-9 views per day, or 30 to 270 views per month.
YouTube takes 45% of ad revenue (https://www.tubefilter.com/2020/02/03/youtube-ad-revenue-how-much-does-youtube-make-from-ads-2017-2018-2019/). Charging $5 for a thousand ad impressions, YouTube would earn $2.25 per 1000 views.
Let's also assume 25% of desktop users use ad block (https://www.statista.com/statistics/804008/ad-blocking-reach-usage-us/). Since 70% of traffic comes from mobile (where ad blocking requires much more effort), we have 2e9 * (0.7) + 2e9 * 0.3 * 0.75 = 1.85e9 non-ad-blocking users.
Putting these together, we'd expect, within a month, YouTube to be making about
30 views / user x 1.5e9 users x 2.25 dollars / 1000 views = x dollars
Putting it into Javascript below, we can check if this gets us somewhere close to YouTube's actual 2019 revenue estimate: 15B USD (https://www.tubefilter.com/2020/02/03/youtube-ad-revenue-how-much-does-youtube-make-from-ads-2017-2018-2019/), or 1.5B USD per month.
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