After more than a quarter of a century on TV, Karl Stefanovic's goodbye to his audience didn't go out on free-to-air television.

"I'm free," a stubbled Stefanovic said in a video posted to his podcast's YouTube channel last week.

Stefanovic's break-up with Nine followed months of speculation that he was looking to move on.

But Stefanovic doesn't appear to have plans to jump to another television network or mainstream media outlet.

He's going "truly independent", Stefanovic said, and will instead focus on his own video podcast, The Karl Stefanovic Show.

So, why is the former king of Australian breakfast television trading studio lights for ring lights?

After all, hosting a commercial breakfast television program has long been one of the most sought-after jobs in Australian media. It's an instant ticket to fame, fortune and influence.

In light of his premature departure, Stefanovic's podcast looks less like a negotiating tactic or a life raft and more like a bet that the future of entertainment and media is online, not on television.

Bringing television to YouTube

When Stefanovic started posting to the YouTube account in late January, the veteran television host brought the lessons he'd learned over a career in broadcast media.

Television is a mass audience medium. Since there's only a handful of broadcast television channels on free-to-air, every minute of air time needs to try to appeal to as large an audience as it can by hiring the biggest names, hitting the broadest topics and having a mix of different formats to keep audiences from changing channels.

From the start, Stefanovic's online world tilted more conservative and culture war adjacent than his broadcast persona. He launched the podcast with an interview with Pauline Hanson, and almost exclusively interviewed right wing politicians and influencers.

But other early guests included MMA fighter Alexander Volkanovski, celebrity chef Curtis Stone, Broncos coach Madge Maguire and radio host Kyle Sandilands with interviews about politics, their personal stories, travel and more.

In other words, much of the early material felt like breakfast television taken online: a variety of guests and topics aimed at a general audience.

Stefanovic's early YouTube efforts achieved modest results. The Karl Stefanovic show quickly gained more than 50,000 subscribers in the first five weeks. But many of his early videos were only watched a few thousand times. One video with Stone talking about sleeping on couches barely cracked a thousand views.

This suggests that Stefanovic's name recognition, his existing social media accounts promoting his new YouTube channel and early mainstream media attention drew people to his new channel, but they weren't actually sticking around to watch videos, nor was he finding YouTube-native subscribers.

Success on YouTube wasn't going to be as simple as doing what he'd always done.

The 'MrBeast' model

After the first initial burst of attention and variable results, Stefanovic kept working away.

The Karl Stefanovic Show has published an average of more than 20 videos a month since it began.

While the output amount was consistent, the type of content began to change. Stefanovic stopped doing broad celebrity interviews on a range of issues and honed in on a few topics.

In the show's first month, January, two videos were about immigration. In June, 14 of the 21 videos on The Karl Stefanovic Show touched on the topic. Politics and government failures became another major focus.

The way he spoke about them changed too. In a video posted last week, he called the passage of Labor's budget tax changes with the support of the Greens a "dirty little deal" that will "kill the Australian dream".

The titles of the videos became more emotive, more alarmed, more aggrieved. Early videos about Hanson had titles like "Does Pauline Hanson Even Want To Be Prime Minister?".

A few months later, the show's One Nation videos had titles like "Australians Don't Trust Politicians Anymore" and "One Nation Senator: 'Australians Are Ready To Swing The Bat'".

Stefanovic has called himself "Joe Bogan" — a reference to successful podcaster Joe Rogan — but the show's strategy reminded QUT's Tim Graham of another popular YouTube personality.

Graham says that the narrowing of the show's content suggests Stefanovic is optimising what he's producing to what performs best online.

"The extreme version of it … is what I call the MrBeast model," he said, referring to the world's most popular YouTube creator Jimmy Donaldson.

While MrBeast is best known for simple, playful stunt videos like "I Filled My Brother's House With Slime and Bought Him A New One", the key to his dominance of YouTube has been his team's reportedly systematic, almost scientific approach to growing his channel with painstaking testing and iteration of everything in his videos.

This approach is necessary because of the sheer scale of YouTube's library. Billions of people go to YouTube each month to choose from hundreds of millions of hours of videos to watch. There are Big Mouth Billy Bass orchestras, tutorials on how to speak dead languages, reviews of paper clips, all in the one place.

To help make sense of the hundreds of hours of videos uploaded every minute, YouTube relies heavily on algorithmic recommendations that suggest videos to people based on data it has about them, including their viewing habits and demographics. Someone who watches model train videos is more likely to be shown another model train video by YouTube, for example.

The culmination of these two factors — an enormous potential audience, and a platform that customises what's shown to you — means that YouTubers tend to be more successful when they stick to one specific niche of content, rather than trying to do a bit of everything.

Stefanovic's journey towards right-wing culture war topics isn't necessarily a revelation of the host's true views, Graham said, but the execution of a content-agnostic strategy based on iterating towards what performed best.

"It's all about asking: what is getting the most engagement? That's what you optimise for," Graham said.

A global ceiling

Stefanovic's split with Nine has been one of the biggest stories in Australian media over the last week.

A soft interview with the far-right anti-immigration figure Tommy Robinson, in which Stefanovic said that he "admired" him, kicked off a new wave of attention that appears to have been the straw that broke the camel's back.

His video announcing the divorce has been his most viewed so far with more than 400,000 views in just a few days.

But Stefanovic's growing online audience isn't just a result of the influence of mainstream media mentions.

As The Karl Stefanovic Show pumped out videos on increasingly specific topics, tones and targets, its subscriber and view counts have steadily grown.

When media attention came along, Stefanovic's channel benefited. Its channel has added a third of its 160,000 followers since last Wednesday. But it grew consistently outside of that, too.

This suggests that Stefanovic isn't just piggybacking off media mentions. His YouTube success has come from acting more like a YouTuber than a big time television host.

And there's no reason to suggest this growth will stop any time soon, particularly as Australians increasingly go online for their entertainment.

The decline of television

Australian television viewership has been declining since the mid-2010s. Now, the average national viewership for a program like Stefanovic's old show is in the low hundreds of thousands.

By comparison, YouTube has more than 2 billion logged-in monthly users. With access to a global audience the hypothetical ceiling for The Karl Stefanovic Show's audience is in the tens, even hundreds of millions.

Even with a hot start, Stefanovic's subscriber numbers still pale in comparison to people like Rogan or fellow television star-turned-YouTuber Piers Morgan with millions of subscribers.

The fact that Stefanovic spent last week in the UK filming videos suggests he's already eyeing an audience abroad.

Comparing online metrics to broadcast television numbers isn't comparing apples to apples; television numbers are the average number of people watching at any one moment while YouTube views count the number of times people have watched at least 30 seconds of a video.

Based on some back-of-the-envelope maths,The Karl Stefanovic Show is still a long way from reaching more people than his old show.

Combining his momentum on the platform with the way that Australian viewing habits are shifting, that might soon change.

(By comparison, Today's own foray into YouTube hasn't had the same success. Despite being 15 years old and having posted more than 900,000 videos, it has just more than 500,000 subscribers and most of its videos receive just a few thousand views at most."

Stefanovic's jump to online video showed a savviness and a willingness to experiment. His early success came from forgetting the lessons of a career in broadcasting in favour of acting like a YouTuber.

The conditions for his move were much larger than just Stefanovic's own circumstances. Mainstream media doesn't hold the sway it once does. New media is ascendant, powered by its enormous reach and its technological advantages.

If the former king of breakfast television is willing to walk away from the throne, it says a lot about where the power in media and entertainment now lies.