If you have kids (or if you’ve read my column before), you might know about know Ryan Kaji, the 7-year-old star of Ryan’s Toy Review on YouTube, who earns $22 million a year because of YouTube.

A 7-year-old toy reviewer who posts videos of his playful critiques and analysis to YouTube is reportedly the video-sharing site’s highest-paid star.

Nine-year-old Ryan Kaji shot to fame opening toys in YouTube videos on his popular channel “Ryan’s World,” spawning a global kids-entertainment franchise across TV shows, streaming channels ...