Still, those figures don’t even capture many of the successful products and businesses influencers have launched, including makeup and clothing lines.

It used to be that digital talent agents were ancillary to the business of big agencies, Mr. Dayeh said. But “in the last two years, digital has become the primary touchpoint for talent with the public.”

To that point, when Brent Weinstein of UTA launched the agency’s digital arm in 2006, initially called UTA Online, he was scouring YouTube and other web platforms for obscure talent. Today, he is the UTA’s chief innovation officer.

Other big talent houses had digital media divisions in the early aughts, too. But at the time, most agencies were focused on bringing celebrities from traditional Hollywood onto then-new platforms like Twitter, rather than building businesses around the ever-growing number of internet-native stars.

“There wasn’t a lot of money going around, it was really early days,” said Alec Shankman, a comanaging partner at A3 Artists Agency, formerly known as Abrams. Now, the dozens of TikTokers the agency has signed, Mr. Shankman said, have “become a really important part of our business.”

That’s partially because influencers are often successful at generating the thing agencies care most about: cash. “Frankly, we’re in a very for-profit business,” said Andrew Graham, an agent in Creative Artists Agency’s digital department. “So when brands started calling and saying, ‘Hey, do you have an influencer for this campaign?’ the agency’s ears perked up.”