YouTube Shorts is experiencing a staggering surge in impressions – but when we break down the numbers, they appear to defy the laws of time, population and even physics. At the same time, YouTube’s CPMs have been falling, leading to an important question: has Shorts given YouTube an explosion in ad inventory, and in doing so, devalued its advertising ecosystem?

YouTube long-form is high-quality. YouTube Shorts is not

There’s no question that YouTube’s long-form content is strong. It offers high-quality production, professionally made content, and strong audience engagement, often consumed on big screens in a lean-back, TV-like experience. Many advertisers increasingly – and rightly – see long-form YouTube as a viable alternative to TV.

But YouTube Shorts is an entirely different product – one that does not deliver TV-like engagement. Some points that marketers and media planners should bear in mind:

• It is typically characterised by low-fi, disposable content. Most Shorts are often repurposed TikToks, memes, or user-generated content with low production value.
• Engagement is fleeting. Users swipe through content at speed, meaning ads are often seen for only a few seconds at best.
• There is a very tiny attention window. Even if an ad is "seen," that does not mean it was absorbed, understood, or remembered.

Yet, many major advertisers are running significant Shorts volumes, these include brands like Woolworths, Westpac, Amazon, Officeworks, and Tesla. The question is: Do these brands truly understand what they are paying for?

The scale of YouTube Shorts is raising some uncomfortable mathematical questions

Google reported in Q1 2024 that YouTube Shorts generates 70-plus billion views per day. That’s an eye-watering number. To put it into perspective:

• That’s nine views per day for every single person on Earth (8bn population).
• Or 13 views per day for everyone with internet access.
• Even more extreme — it’s 573 videos per day for each of YouTube’s 122 million daily active users.

Now, let’s do the maths:

• If the average Shorts view is 6 seconds, that means:
  • 573 videos x 6 seconds = 57 minutes per user per day—meaning every time someone opens YouTube, they would need to spend an hour watching just Shorts. 
  • Even at three seconds per video, users would still be consuming 30 minutes of Shorts every single session. That’s right. 30 minutes of 3 second videos. Every. Single. Session.

Even if we take Google’s numbers at face value, a significant portion of these views may not be meaningful – many could be passive scrolling, autoplay, or users skipping through videos within a second or two. Yet, because impressions are counted after just 5 seconds, this inflates ad impression numbers massively – and that’s where the real shift is happening.

Performance Max (PMax) and the shift in ad budgets

Another factor that may be fuelling this explosion in Shorts impressions is Google’s Performance Max (PMax) campaigns. While PMax does not explicitly favour YouTube Shorts over other ad formats, it automatically incorporates Shorts as part of its overall video advertising strategy.

This means that advertisers running PMax campaigns have likely been allocating significant portions of their budgets to Shorts – without necessarily being aware of it.

• PMax is a black box, optimising towards “performance” across Google’s entire ad ecosystem.
• With billions of Shorts views available at low CPMs, it’s entirely possible that PMax has redirected ad budgets into Shorts impressions, even if advertisers assumed their spend was going toward more premium placements.
• Given Shorts' questionable engagement levels, it’s worth asking: Are these impressions driving real impact, or just inflating reach metrics?

Has shorts flooded YouTube with too much ad inventory?

With ads appearing roughly every 3.4 videos (Source: Adgile), the sheer volume of views means YouTube has unlocked a huge influx of new ad slots. But there’s a problem:

• More ad inventory generally leads to lower CPMs.
• YouTube’s traditional long-form content had limited, premium ad placements, which kept CPMs high.
• Shorts, on the other hand, has drastically increased ad supply, meaning advertisers’ budgets are now spread across far more impressions.

The result? A drop in YouTube’s CPMs. While advertisers may be getting more impressions, those impressions may hold less value if they are simply scraping past the 5-second threshold without real engagement.

A need for greater scrutiny and transparency

The rapid rise of Shorts highlights a broader challenge for advertisers investing in walled garden digital platforms: the lack of independent tracking and auditing.

Unlike traditional media, YouTube:

• Has no third-party verification of audience measurement.
• Does not allow independent auditing of ad delivery and performance.
• Reports on its own metrics, meaning advertisers have no external validation of the data they are given.
• Has known issues with fraud, including crypto scams, fake advertisers, and non-human traffic.

Yet, agencies and brands continue to pour money into these platforms with minimal oversight.

Would we accept this from the traditional media? Absolutely not.

Traditional media is measured independently. Every ad buy is audited, verified, and tracked by third parties to ensure that advertisers get what they pay for.

With YouTube (and Meta, and TikTok), advertisers are trusting the platforms to mark their own homework. And with Shorts, we are yet again seeing the effects of that blind trust – massive, inflated impression counts with little proof of real engagement.

If advertisers are investing significant budgets into YouTube – particularly through automated buying tools like PMax – they should have full visibility into where their ads are running, how they are being measured, and whether they are truly driving engagement.

YouTube can be TV, Shorts cannot

If advertisers are buying premium, long-form YouTube content, they may be getting something vaguely comparable to TV. But if they are buying Shorts – especially through automated buying like PMax – then they are getting a product that is fundamentally different from TV, with far lower engagement and impact.

The explosion of Shorts impressions should be a wake-up call for advertisers to demand more accountability from digital platforms.

More impressions don’t necessarily equate to better outcomes. Without proper scrutiny, it may not be the advertisers who enjoy maximised performance – but YouTube itself.