Forbes, the financial magazine, has proven that there's a lot of money to be earned on YouTube. It has just published its first-ever list of top earners on the video platform, with the irrepressible Felix Kjellberg (better known as PewDiePie) heading the charts with pretax earnings of $12 million, according to Forbes' calculations.

Other figures on the list include comedy duo Smosh ($8.5 million), violinist Lindsey Stirling ($6 million), British video game commentator KSI ($4.5 million), and make-up expert Michelle Phan ($3 million).

Most of those on the Forbes list are under 30 years of change and most of these individuals' income comes from advertising such as sponsored videos and previews, although four of those on the list also have book deals, says cautioned that Forbes' calculations should be taken with a pinch of salt because the list is compiled based on "raw earnings, calculated before management fees and tax." Some of it is "informed guesses".

Forbes says it gathered its data from Nielsen, IMDB, and other sources, as well as on interviews with agents, managers, lawyers, industry insiders, and the stars themselves. So while there may be questions about the accuracy of the calculations, there is no doubt that YouTube is turning into a cash cow for a new breed of young people.

PewDiePie, for instance, has almost 40 million subscribers and is just 25 years old. He earns big for providing expletive-heavy commentary as he plays videogames and millions of fans make up his "bro army". Advertisers are willing to pay a pretty penny to have their products featured in his videos, points out Forbes.

"I thought, if [YouTube] is going to be the global television of the future, I need to build my brand here," said Michelle Phan, who uploaded her first video, a natural makeup tutorial, from a grainy webcam in 2007. "Within the first week, 40,000 people watched it and hundreds of comments came in and that's when I realized I'd found my calling," Forbes quoted her as saying.

Forbes says it identified 10 channels that are cash cows. Videogames and comedy take the cake. Kjellberg is joined on the list by KSI, or Olajide Olatunji, a fellow gamer who made $4.5 million in the past year and broke into the music world with his rap single "Lamborghini" debuting on the UK Top 40 charts.

Comedy winners include Smosh—made up of childhood best friends Ian Hecox and Anthony Padilla—and the Fine Brothers—Benny and Rafi Fine, Rhett & Link, aka Rhett McLaughlin and Charles Lincoln Neal III. The latter has scored sponsored content deals, including with Gillette, Wendy's and Toyota. Lilly Singh, known to her fans as Superwoman, earned $2.5 million over the past year with her jokes, Forbes noted.

The dancing violinist Lindsey Stirling also used YouTube to win fame and $6 million in earnings. Her loyal fan following has enabled her to push two albums into the market, Shatter Me and Lindsey Stirling.

YouTube has, in a sense, come of age and become the new medium whereby young talent can harness millions of fans and in turn become millionaires.