Tom said viewers’ passion counts. “Succession on Sky doesn’t rate very highly — around 200,000 viewers — but they are passionate enough to renew their subscriptions to see the next season, which makes it valuable enough for Sky to pay to fly [its star] Brian Cox over for the programme launch."

He added “As TV shows get more expensive, with more broadcasters collaborating and with more at stake, you probably will find data being used like this. Shows like Amazon’s Lord of the Rings cost the same as a big-budget picture, so you would think they could get audience feedback before putting it out. As things get more expensive, people want more certainty.”

Enders Analysis senior media analyst Jamie MacEwan said: "The timing makes sense.

"Apple probably anticipates increased demand for exposure on the App Store. That's because Apple's iOS privacy changes have made other options less attractive."

Ad campaigns on other sites had less reliable measurements of success, he said.

And app developers ran ads only if they were sure the cost of winning new customers was lower than the amount they would spend on the app.

"As its ads business grows, Apple will have to make sure its execution on consent and privacy is impeccable" to avoid accusations of putting itself first, Mr MacEwan added.

Substack offers software to help people set up free or paid-for newsletters and promises the people creating them that they can write what they want and that they own their own mailing list and can take it with them if they leave.

Substack, they argue, is tearing apart that coalition of workers by ripping out the stars. But Douglas McCabe, media analyst at Enders Analysis, isn’t quite so sure.

“The internet just creates this endless cycle of aggregation, disaggregation, aggregation and disaggregation and that is an internet story, full stop,” he says. Substack “will end up aggregating particular kinds of content and trying to sell a single price point to access these 20 writers who talk about the environment or talk about the future of technology, or whatever it is they talk about”.

Every limit to Apple’s ability to exert control over its own platform is a challenge to its strategy to derive long-term growth from services instead of devices, said Joseph Evans, head of tech at Enders Analysis.

“It’s striking that aside from games and maybe dating apps, there are very few new business models that have really thrived and become extremely profitable through in-app payments,” he said. “The kind of ‘transaction tax’ is probably part of why we haven’t seen as much business model innovation in that area.”