Twitch, YouTube, and other gaming-focused video sites have created an enormous market that attracts a massive global audience, and this sector is on pace to grow this year.

Gaming content on live and on-demand video sites will generate $4.6 billion in revenues this year, according to a report from industry-intelligence firm SuperData Research. This type of media is hastening the replacement of traditional platforms like cable television. More than 20 percent of the people who consume this content in the U.S. fall into SuperData’s “cord-cutters” category — that’s compared to 8 percent of the general U.S. population.

But the market for videos of people shouting while playing Minecraft isn’t an American phenomenon. The worldwide audience for gaming-related livestreams and YouTube creations has ballooned to 665 million, which is more than twice the size of the population of the United States. And with an audience that size — especially one that is avoiding a lot of other media — that’s something marketers and advertisers will want to spend a lot of money to reach.

“’Gaming Video Content’ represents a highly desirable market to advertisers due to the fact that its audience is young, tech-savvy, and willing to spend money,” SuperData research manager Carter Rogers explained. “Companies who do not advertise to GVC viewers risk missing potential customers as they turn to streams over legacy media. With a global audience that reaches more viewers than HBO, Netflix, ESPN, and Hulu combined, brands could be losing out on the next prime-time viewing activity, not unlike TV or sports viewing at their peaks.”

SuperData notes that the average PC and console gaming fan who watches a lot of Twitch or YouTube spends more than $70 per month on digital games, in-game content, and related items. That’s 56 percent more than gamers who don’t watch Twitch or YouTube spend.

And media companies are already spending a lot of money to access those spenders. Of the $4.6 billion that SuperData predicts gaming-related videos will make, $3.2 billion will come from advertising and sponsorships.

And the other 31 percent? That comes directly from viewers, who are spending more and more money to subscribe to or give monetary tips to their favorite creators.