Social media is turning into old-fashioned network television.

A handful of accounts create most of the content that we see. Everyone else? They play the role of the audience, which is there to mostly amplify and applaud. The personal tidbits that people used to share on social media have been relegated to private group chats and their equivalent.

The transformation of social media into mass media is largely because the rise of TikTok has demonstrated to every social-media company on the planet that people still really like things that can re-create the experience of TV. Advertisers also like things that function like TV, of course—after all, people are never more suggestible than when lulled into a sort of anesthetized mindlessness.

In this future, people who are good at making content with high production values will thrive, as audiences and tech company algorithms gravitate toward more professional content.

Meta’s products are a case study in this shift. On the one hand, Instagram head Adam Mosserihas said that in terms of news on Instagram, his focus is to “empower creators.” (He has also indicated that one of his priorities for Meta’s new Twitter-like social Threads is creators, and in a 2022 TED talk, highlighted their ascension.) Meanwhile, his boss Mark Zuckerberghas said that WhatsApp, the messaging app owned by Meta, is the “next chapter” for his company, and since 2019 he has emphasized that, in terms of people connecting through its services, the company will focus on private messaging. Taken together, it’s clear Meta is following the broader industry trend of separating social into private channels, and turning what were once social apps into entertainment feeds.

On these formerly-social platforms, whether content is coming from creators with better equipment and more skills, or Hollywood studios testing the waters, hardly matters. In the end, it will all look remarkably similar to the consumer. It will look, says Daniel Faltesek, a media researcher at Oregon State University, like flipping through cable channels does, only our thumb on the remote has been replaced by our thumb on the screen of our phone, swiping from one TikTok, YouTube Short, or Instagram Reel to the next.

A telling indicator is the rise of a new kind of entertainment professional—the “creator.”

A creator is anyone who records or makes something that can go viral on the internet, says Ursus Magana, chief executive of the creator talent management agency 25/7. His agency gets involved with creators and musicians at the earliest stages of their careers, helping them plan content, update their style, understand what the algorithms of different platforms demand, and connecting them with potentially lucrative brand deals. The company, which was founded in 2021, represents 34 creators and 18 “artists” – that is, musicians.

Six months after signing with a talent agency for creators, Anthony Jabro—Sherman the Verman on YouTube—says, “everything took off, and I went from making no money to making five figures a month.” His videos now garner views in the millions, and between ad revenue from YouTube and paid placement for things like Gillette’s Manscaping line of personal grooming products, he’s now making six figures a year.

While YouTube and TikTok have always been about video, just about every other social-media platform that wants to keep people engaged is emphasizing it more than ever, so that’s what creators have to make, says Magana.

Posting videos to TikTok consistently is essential to getting your songs noticed, says Cade Clair, an emerging musician managed by 25/7, who promotes his work on the platform for up to two weeks before finally announcing on Instagram that it’s being released.

And then there are the actual television shows, and even movies, migrating to social platforms.

On TikTok, there are accounts that shamelessly pirate clips from TV. A good example is all of the clips from the show “House” on TikTok, a show that made its debut before many members of Gen Z were even born. Paramount recently posted the entirety of the movie “Mean Girls” to TikTok for 24 hours as a promotion for the forthcoming reboot of the 2004 film.

TikTok is now more popular than Netflix among consumers younger than 35, according to an October 2022 report from technology-research firm Omdia. Even more telling: In first place is YouTube, the original online TV analog.

Where attention flows, money—and content—must also. In 2023 brands will spend an estimated $6 billion on marketing through influencers—a subspecies of creators—according to Emarketer. Globally, the total addressable market for this kind of marketing is currently $250 billion, according to Goldman Sachs.

Then there is a new generation of shows that are going straight to TikTok, bypassing even streaming services. “Cobell Energy” is a new TV series that is being serialized on TikTok, Instagram and other social platforms. The production company behind Cobell, Yellow Dot Studios, is no mere influencer hype house or fly-by-night creator collective. Yellow Dot was founded by Adam McKay, who wrote and directed the 2021 film “Don’t Look Up,” which was released in theaters and streamed on Netflix, starring Jennifer Lawrence and Leonardo DiCaprio.

In the wake of the success of YouTube and TikTok, Facebook, Instagram, and even LinkedIn are all pushing more and more content made by professionals into our feeds, says Simon Owens, a trade journalist who studies the intersection of traditional media and the growing creator economy.

In order to quantify how TikTok has mastered the art of discerning our interests and feeding us the most compelling possible content, Faltesek, of Oregon State University, conducted a two-year project to study exactly what kind of content TikTok pushes. With a team of students, he created dozens of fresh TikTok user accounts that didn’t like or interact with content in any way—they just let the algorithm play one video after another.

The idea was to see what the base TikTok algorithm tries to hook people with, he says, and the result was transcripts of more than 28 hours of TikTok videos, which his team then classified into different types of content.

At the end of this exhaustive process of gathering data on TikTok’s algorithm, the conclusion became obvious, says Faltesek. “TikTok is television. It flips channels like TV, it provides a flow like TV.”

By this logic, Instagram’s move to copy TikTok, which is in turn encroaching on the turf of YouTube by allowing longer videos, and the increasing dominance of professional content on all three, means they’re all turning into TV. Even Threads, the new offering from Facebook parent company Meta, is fast becoming a broadcast medium for news, as Twitter was before it.

In every case, the structure of social networks has become one in which a handful of accounts create most of the content that others see, and the role of everyone else on the network is, primarily, to amplify and consume that content, says David Rand, a professor at MIT Sloan School of Management.

Where is all this headed? Some, like Magana, believe we’ll eventually see an ever more complete blending of what were once “social” platforms with the traditional television networks and even film studios.

Others, like Staci Roberts-Steele, managing director of Yellow Dot, are finding success on platforms, but aren’t convinced they’ll eat the rest of the entertainment industry. “It’s hard to say this kind of short-form video will be the only kind of TV,” she reflects. “A long time ago, the internet became the new thing, but we still have the other forms on television, and scripted streaming shows. It’s almost like this is just another avenue for that—of watching shows and movies on your phone.”

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Write to Christopher Mims at christopher.mims@wsj.com