YouTube is about to turn 20. An unusual research method is unveiling statistics about the platform that Google would rather keep secret.

YouTube may not seem secretive. It's public facing. You can watch an endless stream of content from now until your dying breath. There's been a mountain of research about the platform, unpacking everything from the commodified economy that surrounds it to the radicalising effects of its algorithm. But the picture goes blurry when you start asking simple questions. For example: how much YouTube do we all watch?

Google, which owns YouTube, is quiet about that and many other details. In February, the company revealed that people who access YouTube on their TVs collectively watch one billion hours a day, but total numbers for the platform are an enigma. Estimates say YouTube has around 2.5 billion monthly users – almost one in three people on Earth – and the average mobile app user watches something like 29 hours a month. With that, let's try some back-of-the-napkin maths.

If we make a few assumptions, and say that monthly viewing average for app users can be applied across all YouTube users on both the website and television, we can multiply 2.5 billion by 29 hours. This would tell us that humanity consumes something like 8.3 million years of videos on YouTube every month. Over 12 months, that adds up to almost 100 million years, hundreds of times longer than the sum total of human history.

How many YouTube videos are there? What are they about? What languages do YouTubers speak? As of 14 February 2025, the platform's will have been running for 20 years. That is a lot of video. Yet we have no idea just how many there really are. Google knows the answers. It just won't tell you.

Experts say that's a problem. For all practical purposes, one of the most powerful communication systems ever created – a tool that provides a third of the world's population with information and ideas – is operating in the dark.

In part that's because there's no easy way to get a random sampling of videos, according to Ethan Zuckerman, director of the Initiative for Digital Public Infrastructure at the University of Massachusetts at Amherst in the US. You can pick your videos manually or go with the algorithm's recommendations, but an unbiased selection that's worthy of real study is hard to come by. A few years ago, however, Zuckerman and his team of researchers came up with a solution: they designed a computer program that pulls up YouTube videos at random, trying billions of URLs at a time.

You might call the tool a bot, but that's probably over selling it, Zuckerman says. "A more technically accurate term would be 'scraper'," he says. The scraper's findings are giving us a first-time perspective on what's actually happening on YouTube.

In its 20 years of operation, YouTube has shaped entire generations' sensibilities and redefined global culture. Surveys show YouTube is the most popular social media site in the US by far, with 83% of adults and 93% of teenagers among its patrons. It's the second-most-visited website on Earth by most estimates, topped only by Google.com itself. But as the platform enters its third decade, the most basic facts about YouTube are still a closely guarded secret.

A Google spokesperson shared a blogpost about the platform's recommendation algorithm, but declined to comment on the statistics and other issues mentioned in this story. For now, YouTube's mysteries continue.

"It's extremely difficult to get a grasp on what's going on inside social media platforms, because while the companies that operate them do make certain public disclosures, those disclosures are fragmentary and often somewhat misleading," says Paul Barrett, deputy........

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